The Rainfall Responses of Typhoon Soudelor (2015) to Radiative Processes of Cloud Species

Abstract

AbstractIn this study, the three‐dimensional Weather Research and Forecasting model is used to conduct sensitivity experiments of Typhoon Soudelor in 2015 to examine rainfall responses to radiative effects of cloud species. Time and model domain mean analysis shows that the radiative effects of cloud ice and snow on rainfall are significantly stronger than those of cloud water and raindrops. The peak of snow appears in the upper troposphere (9 km). The inclusion of radiative effects of snow enhances radiative cooling in the upper troposphere and suppresses radiative cooling in midtroposphere and lower troposphere. The enhanced radiative cooling in the upper troposphere and the suppressed in midmidtroposphere and lower troposphere reduce stability in the troposphere and thus enhance vertical mass divergence and associated divergence of heat flux. The increases in net condensation and rainfall correspond to the increase in release of latent heat associated with the enhancement in divergence of heat flux. The maximum of cloud ice occurs around the tropopause (11 km). The inclusion of radiative effects of cloud ice weakens radiative cooling in the upper troposphere, while it enhances radiative cooling in the lower stratosphere. The weakened radiative cooling in the upper troposphere increases stability in the troposphere and thus reduces vertical mass divergence and associated divergence of heat flux. The reductions in net condensation and rainfall correspond to the decrease in release of latent heat associated with the suppression in divergence of heat flux.