河北省承德市短时强降水的多普勒雷达特征分析

Analysis of Doppler Radar Characteristic of Short-time Strong Precipitation in Chengde of Hebei Province

选取2007年7月至2008年10月承德市39次短时强降水天气的雷达产品资料和常规观测资料,对强降水开始前和强降水期间的雷达反射率因子、径向速度、垂直累积液态水含量、回波顶高等雷达产品进行分析发现:承德短时强降水均由强单体风暴或多单体风暴弥合成的带状、片状积层混合回波造成。短时强降水回波的生成可分为回波移动型、聚合加强型、本地汇聚型、暴雨型4个型;径向速度的基本特征是中低层有入流急流或逆风区,入流急流导致中低层的中尺度辐合和逆风区形成的中小尺度辐合,导致降水回波的汇聚和发展,是形成短时强降水的根本原因。

Based on the radar data of 39 short-time strong precipitation weather events and the routine observation data of Chengde meteorological station from July 2007 to October 2008,the radar data such as reflectivity factor,radial velocity,VIL ,echo tops etc before the beginning and going periods of the strong precipitation were analyzed. The conclusion is that the strong monomer storm or the belt-shaped echo and the laminated mix echo combined by the multi-monomer storm resulted in the short-time strong precipitation in Chengde. The short-time strong precipitation echo could be divided into four types,including echo developing,the polymerization and enhancement,local convergence and the rainstorm pattern. The basic characteristics of radial velocity is that the inflow jet streams or dead wind areas existed in the mid-low layers. The inflow jet streams make the mesoscale convergence in the mid-low layers,and the dead wind areas make the meso-and small scale convergence,which promoted the precipitation echo gathering and developing and resulted in short-time strong precipitation occurrence.