利用多普勒雷达产品诊断分析雷雨大风

Diagnostic Analysis of Thunderstorm Using Doppler Radar Products

利用常规实况场、物理量场、雷达产品资料,对2007年7月30日河南省东北部出现的雷雨大风天气进行诊断分析。结果表明,造成这次强对流天气过程的原因是副高西北侧、槽前深厚的西南气流内产生的飑线发展东北移造成的;持续5 d的深厚低压槽前较强的西南急流,一方面把大量热量、水汽和动量向北输送,使当地具有大量的不稳定能量存储,为对流的发生提供了热力和动力条件,另一方面,高低空深厚一致的西南气流决定了雷雨大风的移动方向。雷达图上,2条回波带的合并形成的"人"字型回波使对流加强,雷雨大风最大风速出现在"人"字型回波顶端及其移动路径上;根据多普勒雷达风廓线上风场的突然上传,可以提前35 min预报雷雨大风天气。

On basis of the conventional field,physical field and radar product information,a strong thunderstorm weather process was diagnosed and analyzed on July 30,2007 in Puyang,Henan Province.It was found that the strong convective weather was caused by the development and movement northeastward of a squall line which was caused by profound southwest flow areas before trough and the northwest side of subtropical high pressure,which transported large amount of heat,moisture and momenta northward by the southwest jet in five days and stored lots of instability energy and provided thermodynamic and dynamic conditions.On the other hand,the move direction of thunder strong wind was decided by high and low levels deep southwest jets.In radar images,two echoes combined into a ＂人＂ shape which strengthened convection.The maximum wind speed of thunder was appeared on the top of ＂人＂ shape and its path.According to the abrupt increase of wind field in Doppler radar wind profile,the thunder strong wind weather can forecast 35 minutes ahead.