热带气旋影响下江苏强对流天气指数分析

ANALYSIS OF SEVERE CONVECTION INDICES ABOUT SEVERE CONVECTIVE WEATHER UNDER THE INFLUENCE OF TROPICAL CYCLONES IN JIANGSU

利用10年资料(2001—2010年)对热带气旋影响下的江苏地区强对流天气的发生规律进行统计,发现在各类强对流天气中,短时强降水天气发生频率最高,其次是雷雨大风天气,一般雷暴很少发生,龙卷和冰雹天气从未发生。统计结果还表明,在这10年中共有21个热带气旋影响江苏地区,多数热带气旋处于向热带低压减弱的阶段。通过对相关个例进行强对流指数研究发现,这些指数的阈值比以往的研究要小,表明受热带气旋影响更容易造成对流不稳定和低层不稳定能量堆积,最终导致强对流天气发生。

Severe convective weather caused by the influence of tropical cyclone （TC） occurred in Jiangsu province was analyzed by various types of severe convective indices during 10 years （2001--2010）. It was found, in such long time series, among all types of the severe convective weather accompanying with TC activities, the events of heavy precipitation typically occurred most frequently, followed by the severe thunderstorm weather. However, the thundered weather without rainfall is rarely happened, and no hail and tornadoes occurred actually. The statistical results also showed that there were 21 landing TCs basically influencing Jiangsu province during 10 years and most of them were on the stage from TC to tropical depression （TD）. The threshold of effectively convective indices of severe convective weather was lower than normal in general, which means that under the influence of TCs, it is more likely to cause convective instability, and the accumulation of instable energy ultimately lead severe convective weather.