Aerosol impacts on clouds and precipitation in eastern China: Results from bin and bulk microphysics

Using the Weather Research and Forecasting model coupled with a spectral-bin microphysics ("SBM") and measurements from the Atmospheric Radiation Measurement Mobile Facility field campaign in China (AMF-China), the authors examine aerosol indirect effects (AIE) in the typical cloud regimes of the warm and cold seasons in Southeast China: deep convective clouds (DCC) and stratus clouds (SC), respectively. Comparisons with a two-moment bulk microphysics ("Bulk") are performed to gain insights for improving bulk schemes in estimating AIE in weather and climate simulations.

For the first time, measurements of aerosol and cloud properties acquired in China are used to evaluate model simulations to better understand aerosol impact on clouds in the southeast of China. It is found that changes in cloud condensation nuclei (CCN) concentration significantly change the timing of storms, the spatial and temporal distributions of precipitation, the frequency distribution of precipitation rate, as well as cloud base and top heights for the DCC, but not for the SC.