HR: 14:00h
AN: A23A-02    [Abstracts]
TI: On the Nature of the Changes in Predictability of Drought and Pluvial Conditions in the U.S. Great Plains over the Last 100 Years
AU: * Schubert, S
EM: siegfried.d.schubert@nasa.gov
AF: Global Modeling and Assimilation Office, NASA/GSFC, Greenbelt, MD 20771 United States
AU: Suarez, M
EM: max.j.suarez@nasa.gov
AF: Global Modeling and Assimilation Office, NASA/GSFC, Greenbelt, MD 20771 United States
AU: Pegion, P
EM: pegion@janus.gsfc.nasa.gov
AF: Global Modeling and Assimilation Office, NASA/GSFC, Greenbelt, MD 20771 United States
AU: Koster, R
EM: randal.koster@gsfc.nasa.gov
AF: Global Modeling and Assimilation Office, NASA/GSFC, Greenbelt, MD 20771 United States
AU: Bacmeister, J
EM: bacmj@janus.gsfc.nasa.gov
AF: Global Modeling and Assimilation Office, NASA/GSFC, Greenbelt, MD 20771 United States
AB: In this study we examine the predictability of extended periods of wet and dry conditions over the central United States using century-long simulations with the NASA Seasonal-to-Interannual Prediction Project (NSIPP-1) atmospheric General circulation model forced with observed SSTs. Moderately large ensembles of runs allow us to diagnose the changes over time in predictability assuming the SSTs are known. Extended (multi-year) periods of enhanced and reduced predictability in both drought and pluvial conditions are diagnosed in terms of changes in the "signal" (forced by the SST) and "noise" (determined by the unpredictable components of atmospheric and land variability). The changes in predictability are interpreted in terms of their dependence on the strength of soil moisture feedbacks, long-term (decadal) changes in the SST, as well as ENSO. The realism of the changes in predictability is assessed by comparing the simulated and observed properties of the seasonal mean precipitation statistics.
DE: 1620 Climate dynamics (3309)
DE: 3319 General circulation
DE: 3337 Numerical modeling and data assimilation
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly