HR: 14:55h
AN: GC13B-06    [Abstracts]
TI: Simulations of the Synoptic Climatology of Extreme Precipitation for Current and Future Climates
AU: * Gutowski, W J
AF: Iowa State University, 3010 Agronomy Hall, Ames, IA 50011, United States
AU: Willis, S S
AF: Iowa State University, 3010 Agronomy Hall, Ames, IA 50011, United States
AU: Patton, J C
AF: Iowa State University, 3010 Agronomy Hall, Ames, IA 50011, United States
AU: Schwedler, B R
AF: Iowa State University, 3010 Agronomy Hall, Ames, IA 50011, United States
AU: Arritt, R W
EM: rwarritt@bruce.agron.iastate.edu
AF: Iowa State University, 3010 Agronomy Hall, Ames, IA 50011, United States
AU: Takle, E S
AF: Iowa State University, 3010 Agronomy Hall, Ames, IA 50011, United States
AB: The skill of regional climate models (RCMs) in simulating the synoptic conditions associated with extreme regional precipitation is assessed using observations from co-operative network observing sites and model results from 10-year RCM simulations of present and future-scenario climates. We focus on extreme daily precipitation events in the Upper Mississippi River Basin region during the cool season (September-March). Extreme regional events are defined as intensities in the top 0.05% that cover several observation sites or model grid points. For both the observed and simulated contemporary climate, nearly all extreme regional events occur when a slow moving, cutoff-low system develops over the Rockies and Great Plains and continually transports moisture into the Upper Mississippi region from the Gulf of Mexico. Results for the future-climate show similar circulation behavior for corresponding extreme events. The magnitude of daily precipitation in future-climate regional extreme events increases by 26%, which considerably exceeds the 16% increase in overall average daily precipitation and suggests that under climate change a greater fraction of cool-season precipitation will occur during extreme events. The results show the potential for RCMs to replicate the synoptic conditions associated with extreme regional precipitation events, supporting their use for projecting future changes in extreme events. The results also suggest robust circulation behavior for such extreme events even under climate change.
DE: 1637 Regional climate change
DE: 1817 Extreme events
DE: 1854 Precipitation (3354)
DE: 3355 Regional modeling
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting