Transcript Initialization of Land Surface Model and its Coupling to CFS

Summer Season Predictions with T126 CFS Using
Different Land Models and Different Initial Land States
Rongqian Yang
Ken Mitchell, Jesse Meng, Helin Wei, George Gayno
Acknowledgments to Suru Saha, Wanqiu Wang, Cathy Thiaw
Environmental Modeling Center (EMC)
National Centers for Environmental Prediction
The 4th Symposium on Southwest Hydrometeorology
Tucson, Arizona, September 20-21, 2007
Outline of Presentation
• Configuration of the CFS land-related experiments
• CFS Skill Masks for JJA: Correlation scores
– Precip
– T2m
– SST
– 200 Mb GPH
• Individual cases:
 Wet U.S. Southwest Monsoon (summer 1999, summer 1990)
 1988 widespread U.S. summer drought
 1993 central U.S. flooding
• Comparing GLDAS/Noah and GR2/OSU initial Soil Moisture
• Conclusions to date
• Ongoing and Near Future Work
CFS Land Experiments: 4 Configurations
Land Experiments of T126 CFS with CFS/Noah and CFS/OSU
Choice of Land Model
Choice of
Land
Initial
Conditions
CFS/Noah
CFS/OSU
GR2/OSU
GR2/OSU (CONTROL)
GLDAS/Noah
GLDAS/Noah Climo
“GR2” denotes NCEP/DOE Global Reanalysis 2
CFS Land Related Experiments
Objective: Demonstrate Impact on CFS of: A) new land model (Noah LSM vs OSU LSM)
B) new land initial conditions (GLDAS vs GR2)
•
25-year (1980-2004) 10-member 6-month T126 CFS runs ( GFS-OP3T3, MOM-3 )
–
•
•
•
•
Four configurations of T126 CFS:
A) CFS/OSU/GR2:
- OSU LSM, initial land states from GR2 (CONTROL)
B) CFS/Noah/GR2:
- Noah LSM, initial land states from GR2
C) CFS/Noah/GLDAS:
- Noah LSM, initial land states from T126 GLDAS/Noah
D) CFS/Noah/GLDAS-Climo: - Noah LSM, initial land states from GLDAS/Noah climo
•
Initial conditions: 00Z daily from Apr 19-23 29,30, and May 1-3
–
5 additional members for A) and C) configurations
Initial conditions: 00Z daily from Apr 24-28
Verification Data Sources
• Precip
- CMAP (also Xie/Arkin)
• T2m
- GHCN/CAMS Global T2m (T126)
• Heights
- GR2 (200mb)
• SST
- OI SST (1x1 to T126)
Next 6 Frames:
Precip Skill Masks: correlation
1) North America
2) Asia
3) South America
JJA Precip Correlation Skill w Different LSMs and ICs
Noah/
GLDAS
Noah/
GR2
Worst
OSU/
GR2
Noah/
GLDAS
Climo
10 Members each case (same initial dates)
15 vs 10 mem JJA Precip Correlation Skills comparison
Noah/GLDAS
OSU/GR2
15
10
15 members results (top row) appear moderately better
Test T126 CFS versus Ops T62 CFS: JJA Precip Correlation
T126 CFS Noah/GLDAS
T126 CFS OSU/GR2
15 Members each case
Caveats:
A) Span of years
Ops: 22-years (1982-2003)
Test: 25-years (1980-2004)
B) Apr-May Initial Dates
Ops: 09-13, 19-23, 29-03
Test: 24-28, 19-23, 29-03
Ops T62CFS (OSU/GR2)
Comparison with Xie/Arkin Precip Anal as Verification Data Source
(future work: will repeat with gauge-only CONUS precip analysis)
Noah/GLDAS
OSU/GR2
CMAP
Xie/Arkin
Use of two different verifying global precip analyses yields similar correlation scores
JJA Precip Correlation Skills over Asia
Noah/
GLDAS
Noah/
GLDAS
Climo
Noah/
GR2
Best
Worst
OSU/
GR2
JJA Precip Correlation Skills South America
Noah/
GLDAS
Noah/
GR2
Best
Noah/
GLDAS
Climo
OSU/
GR2
T2m Skill Masks: Correlation
Next 2 frames
JJA Mean T2m Correlation Skill
w Different LSM/ICs
Noah/
GLDAS
Noah/
GR2
Noah/
GLDAS
Climo
OSU/
GR2
10 Members each case (same initial dates)
JJA Mean T2m Correlation Skill
Comparison
Ops CFS T62 April ICs
Noah/
GLDAS
Best CONUS
10 members
Good CONUS
10 members
OSU/
GR2
Ops
CFS
Noah/
GLDAS
Climo
Good CONUS
10 members
Worst CONUS
15 members
200 Mb Height Skill Mask: Correlation
Next 2 frames
JJA Mean 200mb GPH Correlation Skill w Different LSM/ICs
Noah/
GLDAS
Noah/
GLDAS
Climo
Noah/
GR2
OSU/
GR2
Noah/
GLDAS
Noah/
GLDAS
Climo
JJA Mean 200mb GPH Correlation Comparision
Ops CFS T62 April ICs
OSU/
GR2
Ops
CFS
SST Skill Masks: Correlation
Next 2 frames
JJA
Mean SST Correlation Skill w Different LSM/ICs
Globally
Noah/
GLDAS
Noah/
GR2
Noah/
GLDAS
Climo
OSU/
GR2
10 Members each case (same initial dates)
JJA
Mean SST Correlation Skill Comparison
Globally
Ops CFS T62 April ICs
Noah/
GLDAS
OSU/
GR2
Noah/
GLDAS
Climo
Ops
CFS
Noah/GLDAS Climo seems best, and Noah/GLDAS not so good
Summer Case Studies
1 - Wet U.S. Southwest Monsoon: 1999
2 - Wet U.S. Southwest Monsoon: 1990
3 - 1988 widespread U.S. summer drought
4 - 1993 central U.S. flooding
One frame for each case above:
JJA CONUS precip anomaly: forecast and observed
1999 JJA Mean Precip Anomaly w Different LSM/ICs
Wet Southwest U.S. Monsoon Case 1: 1999
Noah/GLDAS
Noah/GR2
OSU/GR2
Observed
Noah/GLDAS Climo
Climo
CFS with Noah/GLDAS performs the best, OSU/GR2 and Noah/GR2 perform poorly
90 JJA Mean Precip Anomaly w Different LSM/ICs
Wet Southwest U.S. Monsoon Case 2: 1990
Noah/GLDAS
OSU/GR2
Noah/GR2
Observed
Noah/GLDAS Climo
Climo
Noah/GLDAS is the best and Noah/GR2 is the worst
88 JJA Mean Precip Anomaly w Different LSM/ICs
U.S. Major Drought Year: 1988
Noah/GLDAS
Noah/GR2
Noah/GLDAS Climo
OSU/GR2
Observed
Climo
OSU/GR2 performs the best, Noah/GLDAS is not good
93 JJA Mean Precip Anomaly w Different LSM/ICs
U.S. Major Flood Year : 1993
Noah/GLDAS
Noah/GR2
Noah/GLDAS Climo
OSU/GR2
Observed
Climo
Noah/GLDAS is the best and Noah/GR2 is the worst
Soil Moisture:
Comparing
GLDAS/Noah and GR2 initial states
GLDAS/Noah (top row) versus GR2/OSU (bottom row)
2-meter soil moisture (% volume): GLDAS/Noah values are higher
Climatology (left column) is from 25-year period of ~1981-2005)
May 1st Climatology
GLDAS/Noah
GR2/OSU
01 May 1999 Anomaly
GLDAS/Noah
GR2/OSU
GLDAS/Noah (top) versus GR2/OSU (bottom)
2-meter soil moisture (% volume)
May 1st Climatology
01 May 1999
Anomaly
GLDAS/Noah
GR2/OSU
GLDAS/Noah
GR2/OSU
Left column: GLDAS/Noah soil moisture climo is generally higher then GR2/OSU
Middle column: GLDAS/Noah soil moisture anomaly pattern agrees better
than that of GR2/OSU with observed precipitation anomaly (right column: top)
Top: observed 90-day
Precipitation Anomaly
(mm) valid 30 April 99
Bottom: Climatology
Monthly Time Series (1985-2004) of Area-mean
Illinois 2-meter Soil Moisture [mm]:
Observations (black), GLDAS/Noah (purple), GR2/OSU (green)
Total
Climatology
Anomaly
The climatology of GLDAS/Noah soil moisture is higher and closer to the
observed climatology than that of GR2/OSU, while the anomlies of all three show
generally better agreement with each other (though some exceptions)
Conclusions
•
Combined use of the Noah LSM with GLDAS Land States exhibits a
promising indication of improving CFS summer season forecasts of
precipitation, Noah with GR2 combo seems to give the poorest results.
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–
Providing Noah LSM compatible GLDAS ICs is important
Unfortunately, the current public version of CFS scripts still uses
GR2 as default land states. GLDAS Land States should be used.
Ongoing/Near Future Work
• Examine entire atmospheric and land water budget
• Examine the soil moisture influence on seasonal predictions
• Recast skill masks for same 22-year period as ops CFS hindcasts
• Add more performance measures (BSS, RPSS etc)
• Analyze winter-season CFS experiments with land component results
• Re-run CFS/Noah with “Generation 2” of GLDAS/Noah
• Investigate source of land-component impact on Pacific SST
Surface wind stress differences
Thank you for your attention !