关键词: ATOVS资料, 变分同化, 暴雨, TS评分

Abstract:

A regional heavy rain occurred in the southern Shanxi during 3-4 July 2013. In order to study the application effect of satellite data assimilation on the operational numerical weather forecast model in Shanxi, the assimilation with and without ATOVS satellite radiance data by using WRF-3DVAR were experimented and compared. The result are as follows: (1) The analysis field obtained by direct assimilation of the ATOVS satellite radiance could improve temperature, humidity and wind fields of the initial field of prediction, the main performance was increasing humidity in the central and southern of Shanxi and decreasing temperature difference between the southern and northern Shanxi, increasing the westerly component of the middle and lower troposphere, which was more conducive to low-level moisture transportation and gathering to the central and southern Shanxi. (2) The assimilation experiment was better in description of evolution of physical quantities during this precipitation process, especially for the evolution of humidity and vertical velocity over the heavy rainstorm stations. The short-time strong rainfall occurred in the moment that humidity increased and vertical upward movement strengthened, the movement and development of the shear line as a trigger of short-time strong rainfall, convective available potential energy and reflectivity factor had been better reflected. What is more, the location and intensity of the heavy rain had been improved obviously, the TS score of moderate rain or above  had increased significantly, and false alarm rate and false negative rate were decreased.

Key words: ATOVS data, variational data assimilation, a heavy rain process, TS score