Thermal and Microphysical Effects of Ice Clouds on Torrential Rainfall Over Northern China

Ice clouds are an important part of precipitation systems and their thermal (radiative and latent heat) and microphysical effects may impact rainfall. In this study, the thermal and microphysical effects of ice clouds on rainfall are investigated through the diagnostic analysis of rainfall and heat budgets of a torrential rainfall simulation in north China during July 2013. During evening, the maximum reduction in rainfall caused by the inclusion of the thermal effects of ice clouds is mainly associated with the inclusion of latent-heat effects of ice clouds, which suppresses instability and upward motions. During early morning, the maximum increase in rainfall caused by the inclusion of the thermal effects of ice clouds is mainly related to the inclusion of radiative effects of ice clouds, which enhances radiative cooling in the upper troposphere and suppresses radiative cooling in the lower troposphere and thus increases instability and upward motions. The inclusion of microphysical effects of ice clouds increases rainfall directly by the inclusion of deposition and indirectly by the increase in condensation.