Simulation of the effects of sea-salt aerosols on cloud ice and precipitation of a tropical cyclone

Abstract

This study used the Weather Research and Forecasting model with chemistry (WRF-Chem) with a parameterization for the emissions of sea-salt aerosols to assess the effects of sea-salt aerosols on a tropical cyclone. A control simulation (Ctl) and a simulation with a sea-salt emission flux that is one-tenth of that in Ctl (Low) were conducted. Results show that sea-salt aerosols enhance the condensation process, promoting vertical motion and precipitation in a tropical cyclone. Peak precipitation value in Ctl is 120% that in Low. Enhanced vertical motion in Ctl results in increase of water vapor transport to the upper atmosphere, which promotes deposition growth of cloud ice crystals. Therefore, cloud ice mixing ratio and stratiform precipitation in Ctl are larger than those in Low. Stratiform precipitation in the rain band is about 0.5 mm/h in Ctl and about 0.4 mm/h in Low.