Influence of intensive sounding observation data assimilation on the prediction of a vortex rainfall in Sichuan Basin

Abstract the Weather Research and Forecasting Model(WRF) and its assimilation module(WRFDA) are used to assimilate the regular radiosonde data and southwest vortex radiosonde data for predicting a torrential rain in the Sichuan Basin during 29 June to 2 July 2013. The results show that compared with the control experiment, regular radiosonde data assimilation improved the vortex structure and precipitation to a certain extend. Assimilating regular radiosonde data and southwest vortex radiosonde data at a same time can significantly reduce the initial geopotential height in Sichuan Basin, the time that southwest vortex and plateau vortex appears more early than regular radiosonde data assimilation experiment, the coupling of southwest vortex and plateau vortex is more obvious, and the intensity is more stronger. Assimilating regular radiosonde data and southwest radiosonde data at the same time have better skill in simulating this precipitation process. Key words: WRF; Heavy Rainstorm; SWCV