Joint UW-PNNL Climate Science Seminar: Bretherton (UW) and Leung (PNNL)

Start Date/Time: Friday, December 02, 2011, 4:00 PM
Ending Date/Time: Friday, December 02, 2011, 5:00 PM
Location: Guggenheim 415L (also online)

***Joint UW-PNNL Seminar on Climate Science***

This double-header of talks on climate science will include participants at both UW and Pacific Northwest National Lab in Richland, via EVO video conferencing.

Please join us in Guggenheim next Friday, or you can join the EVO meeting "PNNL/UW joint seminar" via

Speakers: Chris Bretherton (UW) and L. Ruby Leung (PNNL)

Chris Bretherton:
"Modeling challenges in prediction of regional rainfall trends in a warming climate"

Global climate models all project that rising CO2 concentrations will warm the tropics and subtropics fairly uniformly, with more warming over land than oceans. However, these models do not agree how regional rainfall patterns will change in these regions, an issue of great importance for the fate of agriculture, ecosystems, and water availability. This talk will give several reasons why regional rainfall trends are harder to project than regional temperature trends, and what kind of modeling strategy might yield more robust regional rainfall predictions.

L. Ruby Leung:
"Development of Frameworks for Robust Regional Climate Modeling"

Predicting the regional hydrologic cycle at time scales from seasons to centuries is one of the most challenging goals of climate modeling. Because hydrologic cycle processes are inherently multi-scale, increasing model resolution to more explicitly represent finer scale processes may be a key to improving simulations of the hydrologic cycle. The robust regional climate modeling project is a multi-lab collaborative effort to use a hierarchical approach to test the veracity of global high resolution, global variable resolution, and nested regional climate model for regional climate modeling. The evaluation hierarchy includes four stages: 1) Idealized, no physics test cases, 2) Idealized, full physics test cases, 3) Real world, atmosphere-only and ocean-only simulations, and 4) Real world, coupled atmosphere-ocean simulations for both current and future climate. At each stage, simulations will be performed using global models at coarse and high resolution, global variable resolution models with high resolution in the area of interest and low resolution elsewhere, and nested regional climate models with the lateral boundary forcing provided by global coarse resolution models. Idealized full physics tests using Aqua-Planet Experiment(APE) have been performed by all modeling approaches. Preliminary analysis of the APE simulations will be presented, focusing on simulations performed using the Weather Research and Forecasting (WRF) model configured as tropical channel and nested regional domains to assess the effects of model resolution and nesting on tropical precipitation.


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