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

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.