28th Annual Climate Diagnostics and Prediction Workshop Reno, Nevada 20-24 October 2003. On the Causes of the 1930s Dust Bowl. Siegfried Schubert, Max Suarez, Philip Pegion, Randal Koster and Julio Bacmeister Global Modeling and Assimilation Office Earth Sciences Directorate.
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20-24 October 2003
Siegfried Schubert, Max Suarez, Philip Pegion,
Randal Koster and Julio Bacmeister
Global Modeling and Assimilation Office
Earth Sciences Directorate
- different ocean basins
- extratropical versus tropical
II. Are land/atmosphere feedbacks important?
IV. Can we predict the next one?
Climatology and Skill (Bacmeister et al. 2000, Pegion et al. 2000, Schubert et al. 2002)
Global grid point dynamical core, 4rth Order (Suarez and Takacs 1995)
Relaxed Arakawa-Schubert Convection (Moorthi and Suarez 1992)
Shortwave/Longwave Radiation (Chou et al. 1994, 1999)
Mosaic interactive land model (Koster and Suarez 1992, 1996)
1st Order PBL Turbulence Closure (Louis et al. 1982)
AGCM runs with Specified SST (C20C project)
HadISST and sea ice dataset (1902-1999)
14 ensemble members - same SST, different ICs
Model resolution: 3 degree latitude by 3.75 degree longitude (34 levels)
Low Pass EOF 2 (PPP)
Residual EOF 1 (ENSO)
PC Time Series
Correlation between PPP and Great Plains Precipitation (low frequency -> 6 years and longer)
Individual ensemble member precipitation
Min = 0.31 max = 0.70,
Ensemble mean precipitation (= 0.74)
Observedprecipitation (= 0.41)
Borchert, John R. “The Dust Bowl of the 1970s”, AAAG, vol 61, March 1971
ABSTRACT: Major droughts in the Grassland region of the central United States have occurred rhythmically during the period of the instrumental record. The time for the next one may be near. ….
“By mid February of 1977 the midwestern US was experiencing one of the most severe droughts in its recorded history … dramatic dust storms blew up in eastern Colorado and western Kansas and Oklahoma …drought was actually most severe in Minnesota and Dakotas …”
“By the fall of 1977 the general drought picture …. had changed significantly”
Symposium on North American Droughts - February 21 1977 (Introduction by Norman Rosenberg, AAAS Selected Symposium 15)