北京首都国际机场暖切初雷天气的特征分析

Characteristics of First Thunderstorm Caused by Warm Shear at Beijing Capital International Airport

针对近两年北京首都国际机场的两次暖切初雷进行研究,总结预报经验,探讨预报的可行性,结果表明：1）两次暖切初雷中,500 h Pa高度层均有浅槽存在,且500 h Pa高度层的正涡度区到达本场附近的时间与雷雨发生时间一致,同时低层有较强的辐合抬升;2）从雷达图像来看,两次雷雨发生时,本场附近均存在明显的速度辐合,雷雨回波为局地生成;3）相当黑体温度（Black Body Temperature,TBB）越低,对流越旺盛,所以TBB等值线图可以用来推断对流的发展趋势;4）在雷雨发生时段,基于风云2号气象卫星的雷暴云指数值介于0-0.5之间,雷暴云指数的变化趋势可以较准确表征雷雨发生的时间。

Two first thunderstorms at Beijing Capital International Airport caused by warm shear was analyzed. The feasibility and success in forecasting the storms is also reported. The results can be summarized as follows： 1） During the two warm-shear thunderstorms, a shallow trough appeared at the 500 hPa level, and the time that the positive vorticity in the 500 hPa layer arrived at the airport was consistent with the timing of the thunderstorm. Furthermore, there was strong convergence in the lower uplift region. 2） From the radar images, it can be seen that an obvious convergence speed appeared near the airport, and the radar echo was generated locally when the thunderstorms occurred. 3） The lower the Black Body Temperture （TBB）, the stronger the thunderstorms. Therefore, the convection development trend can be inferred from the TBB contour map. 4） During the thunderstorm periods, the thunderstorm index value from FY-2E satellite ranged from 0 to 0.5. The value accurately characterized the timings of the thunderstorms.