“7.12”红安特大暴雨地形作用及雷达回波分析

A study on the impact of terrain and analysis on radar-echo on the heavy torrential rainfall event in Hong-an on 12 July 2012

摘要:

利用GFS0.5°×0.5°再分析资料以及卫星、多普勒雷达等观测资料，对2012年7月12日红安特大暴雨过程进行分析，结果表明，大别山复杂山地地形对降水有显著增幅作用，地形影响气流理论很好地解释了此次特大暴雨降水分布，大别山地形迫使西南气流抬升， “指状云团”在大别山迎风坡不断生成，有效的促成后向传播系统，延长了强降水的时间，雷达径向速度场的变化表明，大别山与桐柏山中间的冷暖空气通道对中尺度系统的形成和发展起了重要的作用，雷达回波特征分析表明，0℃层以下大于45dBz回波垂直伸展厚度、垂直液态含水量大小与雨强有非常好的一致性。

Abstract:

By using GFS 0.5 ° x 0.5 ° reanalysis data, satellite data and Doppler radar, the torrential rain in Hong An on July 12th 2012 is analyzed, results show the complex terrain of the Dabie Mountain has significant effects on the increase of precipitation. “Influence of topographic on flow theory” provides a good explanation of the precipitation distribution. The southwest current is forced to lift by the special terrain in Hong An, and the continuously generation of "finger clouds" in the windward slope of the Dabie Mountain which promotes the backward transmission system effectively, extends the period of the heavy rain. The variation of radar radial velocity field shows that the cold and warm air channel between the Dabie Mountain and Tongpai Mountain plays an important role in the formation and development of the mesoscale system. By analyzing the radar echo characteristics, we find that the vertical stretching thickness and vertically integrated liquid water of the echo which is greater than 45 DBZ under 0 ℃ layer, has very good consistency with rainfall intensity.