Aerosol Indirect Effects in UFS from coupling Thompson Microphysics with Water and Ice Friendly Aerosols

Aerosols and clouds continue to contribute the largest uncertainty in the climate and numerical weather modeling and predictions. The aerosol indirect effect (AIE) is one of the largest contributors and a physical realistic representation of AIE has the potential to improve the numerical weather forecasting skills. This study investigates the AIE in the unified forecast system (UFS) with Thompson double-momentum microphysics. Two computational efficient approaches to coupling the Thompson microphysics with aerosol have been compared: 1) The number concentration of water friendly aerosol (NWFA) and ice friendly aerosol (NIFA) are diagnosed from MERRA2 aerosol climatology. 2) NWFA and NIFA are advected and forecasted with sources and sinks derived from MERRA2. The global distribution of AIE, NWFA, NIFA and their relationship with clouds and precipitation are analyzed and compared with observations and former works.