Evaluation of the FY-3E microwave temperature sounding data assimilation on forecasting Typhoon Chanthu (2021)

Abstract Fengyun-3E is the first early-morning-orbit polar-orbiting satellite launched by China, which carries the third generation of Microwave Temperature Sounder (MWTS-3). This instrument has 17 channels and it can provide rich atmospheric temperature observation information at different altitudes. To explore the application value of the MWTS-3 data in assimilation, we selected Typhoon Chanthu in 2021 in this study to evaluate the effect of the MWTS-3 data assimilation on the forecasts of typhoons affecting China. The results show that the simultaneous assimilation of the conventional data and MWTS-3 data can effectively correct the westward error of the typhoon track forecasted by the experiments without assimilation and well predict the track of Typhoon Chanthu along the east coast of China and its stay on the ocean area east of Shanghai. Therefore, the characteristics of the heavy rainfall caused by the typhoon only affecting Shanghai and northeastern Zhejiang are also well reproduced. Compared with the conventional data assimilation, the assimilation of the Fengyun-3E MWTS-3 data provides a more noticeable improvement in the typhoon intensity forecasts, thus allowing better forecasts of the spiral rain belt of the typhoon. The results of the rolling test also proved that MWTS-3 data assimilation has a stable improvement effect on typhoon track forecasts and the forecast skill of precipitation heavier than 5 mm.