Slide 1

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 2

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 3

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 4

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 5

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 6

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 7

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 8

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 9

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 10

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 11

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 12

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 13

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 14

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 15

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 16

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 17

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 18

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 19

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 20

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 21

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 22

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 23

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 24

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 25

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 26

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 27

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 28

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 29

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

29

30

31


Slide 30

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

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31


Slide 31

Research on snow/hydroclimate processes
and trends, integration with CanSISE

Stephen Déry
Marco Hernández-Henríquez
Do-Hyuk “DK” Kang

CanSISE Workshop 1 – Oct. 31st, 2013

1

POLAR AMPLIFICATION AND ELEVATION DEPENDENCE
OF SNOW COVER EXTENT TRENDS IN THE NORTHERN
HEMISPHERE, 1972-2012 – A CONTRIBUTION TO
CanSISE PROJECT C3.1

Marco A. Hernández-Henríquez and Stephen Déry

BACKGROUND
• Recent years have exhibited marked declines in snow
cover extent (SCE) in the Northern Hemisphere,
especially with the springtime offset advancing
(Brown et al. 2010; Derksen and Brown 2012 ).

• In northern latitudes, the snow-albedo feedback is
highest in the spring and amplifies these decreasing
trends in SCE (Déry and Brown 2007).
• Increasing temperatures and precipitation could alter
the declining trends in SCE depending on latitude and
elevation (Brown and Mote 2009).
3

RESEARCH GOALS
• Update the 1972-2006 trends in Northern Hemisphere
SCE presented in Déry and Brown (2007) to include
data from 2007 to 2012 from the NOAA weekly SCE
dataset maintained at Rutgers University.
• Examine latitudinal and elevational variations in the
presence of snow
• Observe trends in snow coverage with latitude and elevation.
• Determine if there is latitudinal and elevational dependence of
snow cover over time and potential impacts to the surface
radiation budget.
4

METHODS
A. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by 1o
latitudinal bands and at continental scales.
i.

Computed trends in the fraction of time that a latitude
band is snow-covered over the study period.

ii. Plotted trends in the total area of snow cover as a
function of latitude.
iii. Assess snow coverage trends by climatological snow
cover fraction.

5

METHODS
B. Linear regressions are used to investigate trends in
snow coverage (significant when p < 0.05) by
elevation bands of 100 m.
i.

Computed trends in the fraction of time that each
elevation band is snow-covered over the study period.

C. Assessed absolute, standardized and solar insolationweighted trends (significant when p < 0.05). The latter
are computed by multiplying absolute SCE values by
the ratio of the weekly average and annual maximum
incoming solar radiation at 60oN.
6

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

7

8

9

Large dots indicate significant trends
(black = p < 0.05 and red = p < 0.0001)

10

Dots indicate significant (p < 0.05) trends

11

Dots indicate significant (p < 0.05) trends

12

13

CONCLUSIONS
The retreat of Northern Hemisphere snow cover has
accelerated in recent years with the strongest trends at
high latitudes and with most frequent snow coverage.
The greatest potential impacts to the surface radiation
budget are at high latitudes (60-70oN) during spring.
These results provide further evidence of a polar
amplification of snow cover extent trends, with the snowalbedo feedback enhancing the trends.
14

The changing contribution of snow
to the hydrology of the Fraser River Basin
– A contribution to CanSISE Project B3
Do-Hyuk ‘DK’ Kang1 , Xiaogang Shi2, Huilin Gao3
and Stephen Déry1
1Environmental

Science and Engineering Program
University of Northern British Columbia
2National Hydrology Research Centre
Environment Canada
3Zachry Department of Civil and Environmental Engineering
Texas A & M University
October 31st, 2013

Northern Hydrometeorology Group, UNBC

VIC model application to the Fraser
River Basin (FRB)
• The Variable Infiltration Capacity (VIC) model
has been applied to the Fraser River Basin
(Liang et al. 1994; 1996).
• The model is run at ¼◦ and is forced by daily
atmospheric conditions sourced from Shi
(2012).
• The calibration period spans 1949-1968 and
the validation period covers 1969-2006
• Trends assessed with Mann-Kendall Test
(significant when p < 0.05).

Air Temperature

Precipitation

NSE = 0.93 (Calibration)
(0.86)
NSE = 0.85 (Validation)

r = 0.75

RSR = SWEmax/R
r = 0.84

CONCLUSIONS
FRB air temperatures have warmed by 1.5oC while
precipitation remained stable over water years 1949-2006.
This has led to significant declines (~100 mm SWE) in snow
accumulation across the FRB.
Over the period of study, the contribution of snow to runoff
generation for the Fraser River at Hope, BC has declined by
22% and it is transitioning to a hydrid/pluvial system by
~2025-2045.
24

INTEGRATING CANSISE RESEARCH
– RESEARCH COLLABORATION
• Closely collaborating with C. Derksen and R. Brown for their data
input, acquisition, and expertise.
– DATA ACQUISITION
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have
kindly provided the National Oceanic Atmospheric Administration
(NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask).
– REGIONAL CLUSTERS
• Stephen recently participated online in the “Eastern Cluster” regional
meeting held in Waterloo.
– MEDIA ATTENTION & OUTREACH
• A press release announcing the CCAR funding received by Stephen
as part of the CanSISE was issued by UNBC on June 24th, 2013.
Following this, Stephen conducted a series of interviews with local
media, including CBC Radio Prince George, the Wolf radio station,
and CKPG television.

INTEGRATING CANSISE RESEARCH
- RESEARCH COLLABORATION
• Closely collaborating with Dr. Dennis Lettenmaier’s group at University
of Washington for the VIC model application and UW alumni Huilin
Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada).
• Further collaboration with hydrologists at PCIC for future projections
of Fraser River Basin hydrology (2013/11/1)
- CANSISE OUTREACH & DISSEMINATION
• Stephen led an interactive discussion on watershed stewardship in the
context of climate change with the Northern Provincial Government
Water Stewardship Group at UNBC (2013/10/9).
• DK presented recent progress on hydrologic simulations of the FRB at
Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

ACKNOWLEDGEMENTS
• D. A. Robinson and T. Estilow from Rutgers Global Snow Lab
for providing the SCE and ancillary data.
• R. Brown (Ouranos) and C. Derksen (Environment Canada)
for data and assistance with this work.
• D. Lettenmaier, X. Shi and H. Gao for assistance with VIC
model implementation over the Fraser River Basin.
• Funding provided by the government of Canada’s NSERC
CCAR initiative grant awarded to the CanSISE Network.

27

REFERENCES
Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of
variability and change in Arctic spring snow cover extent, 1967–2008, J.
Geophys. Res., 115, D16111, doi:10.1029/2010JD013975.
Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere
snow cover to a changing climate, J. Clim., 22, 2124–2145,
doi: http://dx.doi.org/10.1175/2008JCLI2665.1.
Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in
the 2008–2012 period exceeding climate model projections, Geophys. Res.
Lett., 39, L19504, doi: 10.1029/2012GL053387.
Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover
extent trends and implications for the snow-albedo feedback, Geophys.
Res. Lett., 34, L22504, doi: 10.1029/2007GL031474.
28

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30

31