Simulations of Extreme Events Using WRF Driven by Two GCMs (Invited)

As part of the North American Regional Climate Change Assessment Program (NARCCAP), the Weather Research and Forecasting (WRF) model has been used to downscale two sets of global climate change scenarios simulated by the Community Climate System Model (CCSM) and Canadian Global Climate Model (CGCM) for the present (1970-2000) and future (2040-2070) for North America. Previous analyses based on the CCSM-driven WRF simulations have focused on the warm season precipitation and severe weather environment in the Great Plains as well as cold season heavy precipitation associated with the atmospheric rivers in the western U.S. Our results based on analysis of severe weather proxies such as CAPE and SHEAR show an increase in severe weather in the northern Plains due primarily to increases in CAPE under global warming. Our results also show an increase in atmospheric river induced heavy precipitation along the west coast due to both increased frequency of atmospheric rivers and increased atmospheric moisture under global warming. Analyses are now being performed to compare the two sets of climate change simulations driven by CCSM and CGCM, with a focus on how the large scale boundary conditions influence the regional climate change signals related to extreme events.