Modeling Aerosol-Cloud-Climate Interactions over East Asia
Atmospheric aerosol loadings have been increasing in the last few decades over Asian monsoon regions due largely to increased emissions of aerosol-precursors from fossil fuel consumptions. The increases in aerosols directly scatter and absorb the solar radiation and, to a less extent, trap the thermal radiation, and indirectly change the cloud optical property by altering cloud microphysics with subsequent effects on life cycle of clouds. A collaborative effort in the present project to study the aerosol climate effects over East Asia is to incorporate a physical-based, statistical-numerical, two-moments (mass and number) cloud scheme (formulated by Jen-Ping Chen) into the global climate model developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) of the Institute of Atmospheric Physics, Chinese Academy of Sciences, and the regional WRF model. While the global modeling effort is aimed at studying climate changes on the seasonal to decadal time-scales, the WRF modeling effort is for understanding the processes affecting the cloud macro- & micro-physical properties, radiation and meteorology. Significant progresses have been made and both modeling effort will be reported. For LASG global model, multi-component aerosols (sulfates, dust, black carbon, sea salt, and organic aerosols) have been included, and a control simulation for the present climate is currently being evaluated and used to contrast the simulation without aerosols. For WRF model, two case studies were conducted to study the aerosol effects on: (1) the macro- & micro-physical properties of stratocumulus over the Southeast Pacific ocean during the October-November 2008 VOCALS (Variability of the American Monsoon System/ Ocean-Cloud-Atmosphere-Land Study) Campaign, and (2) the subgrid-scale dynamics and microphysics in convective clouds during the May 15-June 30, 2008 TIMREX (Taiwan Island Monsoon Rainfall EXperiment). Study findings will be highlighted and specific issues related to aerosol-cloud-climate interactions will be discussed.