卫星资料在山西暴雨数值预报中的初步应用

Preliminary Application of Satellite Data in Numerical Prediction of Torrential Rain in Shanxi

旨在应用卫星云顶数据改进数值模式的水汽初始场,探讨利用卫星资料改进定量降水预报的可能性。利用ADAS(ARPS Data Analysis System)综合云分析系统,将静止卫星云顶亮温数据加入到WRF中尺度模式中,对2013年7月9日夜间山西南部一次暴雨过程进行数值模拟和对比试验。结果表明:此次强降水过程发生在高空槽引导西北涡东移的环流背景下,低涡切变线附近生成的中-β尺度强对流云团是造成此次强降水的直接影响系统。融合卫星云顶数据改善了模式24 h降水预报效果,有效减少强降水的空报,显著提高暴雨以上强降水的预报效果。进一步分析表明:融合卫星云顶数据后,模式可以获取中尺度系统信息,可以捕捉中-β尺度强对流云团;模式有效加强了对降水有重要影响的高湿区的分析,动力场能够快速协调适应;模式更加有效地预报出未来3 h内降水模态的变化和移动,显著改善了强降水的临近预报效果。

In order to improve the water vapor initial field of numerical model and QPF （quantitative precipitation forecast） with the satellite data fusion, the numerical simulation and sensitivity experiment were made on a short-term severe precipitation process occurred in southeastern Shanxi Province at night of July 9, 2013. The results showed that： the northwest low vortex moving eastward with the upper-level trough guiding was the circulation background for this severe precipitation, and the short-term severe precipitation process was mainly affected by the low-level vortex accompanied by wind shear, while the meso-β scale convection cloud system which generated near the shear line was the direct system. Precipitation forecast for 24 hours, especially forecast of severe precipitation, could be improved significantly by cloud top data fusion. Further study indicated that： cloud top data fusion could contribute to obtaining the information of mesoseale systems and finding out the meso-β scale convection cloud cluster; with the cloud top data fusion, numerical model could better depict the mesoscale characteristic of real humidity field, significantly enhance the analysis of high humidity regions which had an important influence on the severe precipitation; numerical model could more effectively forecast the change and movement of precipitation for 3 hours, which would significantly improve the effect of rainstorm nowcasting.