西宁两次强降水的雷达VWP特征
Characteristics of VWP on Xining Radar during Heavy Rainfall Events
中文摘要：
分析了西宁2次不同性质强降水的雷达径向速度和风廓线产品（VWP）特征，结果表明：西宁强降水开始前低层西南（SW）风速增大，中层风场出现“ND” （静止风），高层偏东风明显。过程最大降水量出现在低层风向明显转变的时段内。混合性强降水在高层强气流向下传递至低层时强降水开始或增大，强降水偏向高空平均气流的右侧；对流性强降水主要是低层强气流向下传递，偏向高空平均气流右侧的幅度较小；中层ND楔形块是强降水开始的先兆。
中文关键词：
强降水，雷达VWP，垂直风切变，风暴相对螺旋度，强降水指数
KeyWords：
heavy precipitation, VWP on the radar, vertical wind shear (|△V|), storm relative helicity (SRH), heavy precipitation index
Abstract：
The characteristics about VWP during two different properties of heavy rainfall events on Xining radar are analyzed, the results show that the wind speed of SW at the lower level increases, ND appears at the middle level and the E-flow at the high level is obvious before the beginning of heavy precipitation in Xining. The maximum precipitation in the process occurs during the period when the wind direction at the low level changed significantly. The heavy precipitation begins or increases when highlevel strong air flow are transmitted downward to the low level and it is biased to the right of the upper airflow during the mixed heavy rainfall event, while the low-level strong airflow mainly transmitted downward and the bias amplitude to the right is smaller during the convective heavy rainfall event, and the appearing of ND wedge block at the middle level is a harbinger of the heavy precipitation.