Improving “23.07” Heavy Rainstorm Simulation Through Assimilating FY-3E MWTS-3 Radiance Data

FengYun-3E (FY-3E) satellite, launched on 5 July 2021, is equipped with the third-generation Microwave Temperature Sounder (MWTS-3). Two window channels of MWTS-3 are used to build a cloud detection module, and efficient assimilation of MWTS-3 clear-sky radiance data is implemented in the Weather Research and Forecasting Model (WRF). To assess the influence of assimilating MWTS-3 radiances on extreme precipitation weather forecasting, a heavy rainstorm event that occurred in North China from 29 July to 2 August 2023, has been selected. After assimilating MWTS-3 radiance data, the geopotential height field adjusted, leading to a northwestward shift of the Western Pacific Subtropical High as well as an eastward adjustment of the weather system. The forecasts with assimilated MWTS-3 data reduced the root mean square error of temperature, zonal wind, and meridional wind, with clear improvements in temperature forecast skill at the 100–400 hPa levels within the first 33 hr of the forecast period. The 6–hr maximum rainfall center located southwest of Beijing was more successfully reproduced in the model simulation. Additionally, the precipitation forecast skill above the threshold of 15 mm was improved. Moreover, the water vapor transport and vertical motion conditions in Beijing has improved after assimilating MWTS-3 data, which are likely to be contributing factors to the enhancements in the precipitation forecasting performance.