land analysis in the noaa cfs reanalysis...gr2 1999 cpc 90-day obs precip anomaly ended 30apr1999...
TRANSCRIPT
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Land Analysis in theNOAA CFS Reanalysis
Michael Ek, Ken Mitchell, Jesse MengHelin Wei, Rongqian Yang,
and George Gayno
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Outline• CFS Reanalysis execution• Land surface model upgrade from OSU to Noah• LIS/GLDAS infrastructure• Observed precipitation forcing• CFSR streams and overlapping• Reanalysis results
– 30-year climatology of global soil moisture field• CONUS regional time series
– Compare to GR2, NARR, and Illinois observations– Spinup, trend, variability, and anomaly
• CONUS May climatology and anomaly
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0Z GSI 6Z GSI 18Z GSI
0Z GODAS
0Z GSI
CFS Reanalysis Execution (24-hr span) : Note daily GLDAS
6Z GODAS 12Z GODAS 0Z GODAS
12Z GSI
18Z GODAS
Atmos. Analysis
Ocean Analysis
12Z GLDAS6Z GLDAS 18Z GLDAS 0Z GLDAS0Z GLDASLand Analysis
Time
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GFS and CFS: Land Model UpgradeNoah LSM (new) versus OSU LSM (old):
• Noah LSM (vegetation, snow, ice)– 4 soil layers (10, 30, 60, 100 cm)– Frozen soil physics included– Add glacial ice treatment– Two snowpack states (SWE, density)– Surface fluxes weighted by
snow cover fraction– Improved seasonal cycle of vegetation– Spatially varying root depth– Runoff and infiltration account for sub-grid
variability in precipitation & soil moisture– Improved thermal conduction in soil/snow– Higher canopy resistance– Improved evaporation treatment over bare
soil and snowpack
• OSU LSM– 2 soil layers (10, 190 cm)– No frozen soil physics– Only one snowpack state (SWE)– Surface fluxes not weighted by
snow fraction– Vegetation fraction never less than
50 percent– Spatially constant root depth– Runoff & infiltration do not account
for subgrid variability of precipitation & soil moisture
– Poor soil and snow thermal conductivity, especially for thin snowpack
Noah LSM replaced OSU LSM in operational NCEP medium-rangeGlobal Forecast System (GFS) in late May 2005
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Land Information System
Noah LSM CFSRland analysis
Soil MoistureSoil Temperature
Snow
Land SurfaceCharacteristics
Topography Land Cover
Soil
Non-precipMeteorological
Forcing
PrecipitationForcing
Land VariablesSoil Moisture
Soil TemperatureSnow
CFSR surface file
gdas1.t00z.sfcanl
Christa Peters-Lidard et al., NASA/GSFC/HSB
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Motivation for Using Observed Precipitation in CFSRGDAS high bias in tropical precip compared to CMAP analysis
10 July – 09 Aug 2007 ExampleDifference Plot
GDAS yields high precip bias in tropics.
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Unified Daily Gauge Data Dense gauge networks from special CPC collections
over US, Mexico, and S. America; GTS gauge network elsewhere Daily reports available from ~17,000 stations
Mingyue Chen and Pingping Xie
A blended precipforcing is used withthe heavier weights ofCFS/GDAS – high latsGauge – mid latsCMAP – tropics.
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CFS Reanalysis Streams
1980 1985 1990 1995 2000 2005 2010
14 mo
12 mo
12 mo
12 mo
12 mo
Productionoverlap
All streams use the mean 2006-2007land states from operational GDASof each given start date as the land initial conditions.
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• Overlapping between streams isessential.
• With at least 12-month overlapping,the discontinuity between streams isreduced.
• GR2, while executing one singlecontinuous stream, also showed anupward trend over the past two decades.
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CFSR Soil Moisture Climatology
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CFSR Soil Moisture Climatology
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CONUS 2-meter soil moisture [%]SMC Total SMC Anomaly
CFSR – 6 streams GR2 – 1 stream
Trend? Natural or model driven?
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Illinois 2-meter soil moisture [mm] Total
Anomaly
R(GR2,OBS)=0.48 R(NARR,OBS)=0.67 R(CFSR,OBS)=0.61
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CONUS soil moistureMay climatology and anomaly
CFSR climatology
GR2 climatology
CFSR 1988 drought
GR2 1988 drought
CFSR 1993 flood
GR2 1993 flood
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CONUS soil moistureMay climatology and anomaly
CFSR 1999
GR2 1999
CPC 90-day obs precip anomalyended 30Apr1999
CFSR soil moisture anomaly correspondswell with observed precip anomaly.
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Land Surface Water Budget30-year mean annual cycle, 1980-2008
precip evap
runoff soil moisture
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Summary• LIS/GLDAS as the land analysis of CFSR• Noah land surface model upgrades• A blended forcing to utilize observed precip to reduce the
impact of forecast model bias• Overlapping reduces the discontinuity between CFSR
streams.• Result shows reasonable soil moisture climatology and
anomaly.• Further analysis given in the companion two posters:
J. Meng et al., and R. Yang et al.• Reanalysis as initial conditions for Reforecast• Guidelines for future land surface model development• For CFSR data access at NCDC:
http://nomads.ncdc.noaa.gov/NOAAReanalysis/cfsrr