Impacts of regional climate change upon the warm rain process and surface precipitation from deep convective storms: A numerical modeling study.

摘要

Multiple studies have stated that precipitation changes resulting from climate change are reflected mainly in the heavy and extreme daily precipitation events, at the expense of more moderate events. Observations in the contiguous U.S. over the 20th century have shown that these precipitation changes have been larger in the summer months. However, the details of how precipitation production within deep convective storms will be modified as regional climates change are still not well understood, owing to the complex interactions between microphysical processes, thermodynamic aspects of the atmosphere, the cloud dynamics, and the large-scale environment. This study investigates if storms developing in a warmer, moister future environment can be expected to have a more active warm rain process, and if so, how it may affect ice processes aloft and precipitation at the surface.;A detailed 1D microphysical model and the 3D Weather Research and Forecasting (WRF) model are both used to simulate continental convective storms at different sites within "past" (1970-1999) and "future" (2070-2099) environments derived from NCAR CCSM3 model output. Results suggest future storms will be dynamically stronger with shorter lifetimes, but producing more rain and less hail within the storms, and higher rainfall rates at the surface. The warm rain process is more important in the initial rain production in the future storms; but the contribution of ice processes to surface rainfall is decreased. The precipitation efficiency of the future storms show higher values owed to the increased productivity of the warm rain process.