The stratosphere–troposphere exchange process during typhoon Molave (2020)

Typhoon is a significant source of deep convection which plays an important role in stratosphere–troposphere exchange (STE) in the Northwest Pacific Ocean. In this study, Typhoon Molave (2020) was simulated by using the Weather Research and Forecasting model (WRF) to examine the STE process and its detailed characteristics compared with the results from ERA5. The geopotential heights and wind field indicate existence of gravity waves (GWs) which transport large amounts of energy through the atmosphere. GWs also allow airmass exchanges between stratosphere and troposphere. A joint analysis of driving field reveals strong linkage between GWs and ozone variations over the region. A significant increasing response of the upper troposphere and lower stratosphere (UTLS) ozone to the gravity wave in areas near the typhoon path. The GW activity caused by typhoon Molave leads to turbulent flow, the mixing of momentum and air mass.