Transcript Climate Research in Nepal Himalayas Saraju K. Baidya

Climate Research in Nepal Himalayas
Saraju K. Baidya
(Department of Hydrology & Meteorology)
“Mountains, witnesses of global changes. Research in the Himalaya and Karakoram:
SHARE-Asia Project”, 16-17 November 2005
Physiography
Meteorological Station Network
•
•
•
•
•
•
•
Latitude (°N)
30
29
Precipitation 337
Climatic
68
Agro-met
22
Synoptic
9
Aero-Synoptic 6
Total
442
Automatic
16
28
27
81
82
83
84
85
Longitude (°E)
86
87
88
Spatial Distribution of Mean Monsoon
Precipitation (mm)
Altitude determines the
spatial distribution of
rainfall
30
Latitude (°N)
29
28
27
80
81
82
83
84
Longitude (°E)
85
86
87
88
Climatic Trends in Nepal
Maximum Temperature
Trends in the Himalaya
(1971-94)
Shrestha et. al, 1999
Nepal Summer Monsoon Rainfall Trend
1800
1600
1500
1400
1300
1200
y = 3.2325x + 1449.2
1100
R2 = 0.0421
1999
1997
1995
1993
1991
1989
1987
1985
1983
1981
1979
1977
1975
1973
1000
1971
No significant trend in rainfall
Rainfall (mm)
1700
Climate Research
The glaciological and meteorological observations in Nepal
Himalayas started in 1973 and 1974 as the "Glaciological Expedition
to Nepal (GEN)".
Nepal Himalayas: 2% of World’s Freshwater
Snowmelt:10% of annual flow
The studies show that these glaciers are retreating at an alarming
rate.
Many researches in this field highlight the impacts on water
resource management and Glacier lake outburst Floods (GLOF).
Snow and Glacier Studies
Activities
Humla
Kanjiroba
Operation of 7
Hydrometeorological stations
Hydrological and
Meteorological data (Elevation
2700 - 4300 m) collection and
publication
Glacier and glacier lake studies
Model development for snow
and glacier melt runoff
Annapurna
Langtang
Tsho Rolpa Dingboche
Makalu
Parameters
(i) Temperature
(ii) Relative Humidity
(iii) Precipitation
(iv) Solar radiation
(v) Wind speed/ direction
(vi) River stage/discharge
(vii) Water equivalent of
snow
Gauging Stations, Annapurna Region
Automatic Water Level Recorder,Langtang
Khumbu
Automatic Weather Station
Snow survey for
determination of water
equivalent of snow
Snow pit
Snow sampler
Retreat of AX010 Glacier
Retreat from 1978-1989
Was 30 m
Imja Lake (Khumbu region)
SOURCE: WECS
2002 Area: 0.86 Km2, 14.7% more than in 1999
SOURCE: DHM
Climate Change Studies
Nepal Himalayas are highly vulnerable to the climate
change. It has wide impact on water resources and
agriculture of Nepal
His Majesty’s Government (HMG) of Nepal instituted a
Country Study program on Climate Change in 1994 under
the support of US Country Studies Program.
For the first time in Nepal, General Circulation Models
(GCMs) Outputs were used and climate change scenarios
were developed.
Climate Change Studies
• Four models
– CCCM: Canadian Climate Centre Model (2 Grid pts.)
– GFD3: Geophysical Fluid Dynamics Laboratory R-30 Model
(2 Grid pts.)
– UK89: United Kingdom Meteorological Office Model (2 Grid
pts.)
– GISS: Goddard Institute of Space Science Model (1 Grid pt.)
Climate Change Studies
• For 2XCO2 (22 stations)
– Precipitation increase
• CCCM : 36%
• GFD3: 67%
– Increase in Monsoon season and decrease in dry (winter)
season
– Temperature increase
• CCCM: 1.4oC to 4.1oC; 2.9oC
• GFD3: +1.7oC to 4.2oC; 3.1oC
• Limitation: low resolution
Status of Climate Models in
Nepal
• Rough topography of Nepal requires high resolution
models
• Currently Nepal is experimenting on two RCMs
– RegCM3 (ICTP, Italy)
– PRECIS (Hadley Centre, UK)
• Main aim of these models is to study the impact of
climate change
• Currently, we are on the process of validation
experiments
RegCM3 Results of 1997 June
30 km
30
Observation
29
28
27
0
-100
80
50 km
50 km
100
81
300
500
82
700
900
83
1100
84
1300
1500
85
86
75
75km
km
87
88
RegCM3: 1997 monsoon Nested
Observation
30
29
28
27
-200
0 200 400 800 1200 1600 2000 2400 2800 3200 3600 4000
80
81
82
83
75 km
84
85
86
87
88
Nested: 15 km
Time required for 1 month simulation
Approximate time required (days)
9
8
8.0
7
6
5.3
5
4
3
1.3
2
0.7(16hrs)
1
0
15
30
50
Horizontal Resolution (km)
• Major issues Running RCM
75
– Time constraint to run high resolution models
– Computing facilities
Monsoon Study
• A project was developed in
1999 and number of
meteorological stations
ranging from 500 m to 4400
m were installed in the
Marsyangdi river basin in
central Nepal and Monsoon
Himalayan Precipitation
Experiment (MOHPREX)
was carried out during June
2001 to study the
interaction of the Himalayas
and the Asian summer
monsoon
Source: Ana P. Barros and Timothy J. Lang (2001)
• The
mountains act as
barriers to the south-easterly
monsoon flow from BOB and
consequently
low
level
convergence occurs.
• Upslope and upvalley flows
reduce this convergence. The
upslope flow leads to high
level
convection
and
secondary
peak
in
precipitation.
Source: Monitoring the Monsoon in the Himalayas: Observations in Central Nepal,
June 2001, Ana P. Barros and Timothy J. Lang
• with the absence of upslope
winds, and prevalent down
slope
winds,
strong
convergence of the moist
advected
monsoon
flow
occurs which acts to force
convection which lead to the
nocturnal peak in rainfall in
these areas.
Concluding Remarks
• Nepal deserves special attention in climate related
research because
– Complex Topography
– Himalayas are highly vulnerable to climate change
– Himalayas are the water tower for South Asia where
most of the poorest people live
– Himalayan range plays an important role in Asian
Summer Monsoon
• Need of special research on Climate models in
Himalayan regions
Thank You