新一代天气雷达径向速度质量分析

Analysis of Radial Velocity Quality of CINRAD

径向速度的模糊问题是制约新一代天气雷达径向速度资料应用的关键问题,且影响制约速度退模糊效果好坏的因素比较多。利用上海站和舟山站雷达资料,分析WSR-88D天气雷达和国内新一代天气雷达(SA、SB)径向速度资料质量上的差异,同时利用南京站、广州站及承德站雷达资料,详细说明信噪比对新一代天气雷达(SA、CB)径向速度质量的影响。从理论分析和个例资料的分析中发现:SA(SB)雷达相对于WSR-88D雷达而言,径向速度值跳跃性较大;同时,信噪比与径向速度质量及速度模糊之间存在一定的关系,信噪比越大,径向速度差值相对越小,则径向速度跳跃性较小,径向速度资料质量相对较好,发生速度模糊的可能性就越小;反之,信噪比越小,径向速度差值相对越大,则径向速度跳跃性较大,径向速度资料质量相对较差,发生速度模糊的可能性就越大。

Velocity measurement aliasing is an operational challenge in using Doppler radar velocity field,moreover,there are many factors that affect and restrict the effect of velocity dealiasing,so the quality of different types of radar radial velocity data and the effects of signal- to- noise ratio on velocity aliasing and velocity dealiasing were analyzed in this paper. By using radar data from Shanghai and Zhoushan stations to calculate radial velocity（ Vi） of all gates and the difference of radial velocity of adjacent gate（ △V）,the difference of WSR- 88 D radar and Doppler Radar of China（ SA,SB） radial velocity data quality were analyzed. At the same time,using the data from Nanjing,Guangzhou and Chengde radar to calculate △V and corresponding signal- to- noise ratio,the effect of signal- to- noise ratio on velocity dealiasing and local velocity change of Doppler Radar of China（ SA,CB） were elaborated. Through theoretical analysis and the analysis of example data,it was found that the values of radial velocity of SA radar had a larger leaping in relative terms of the WSR- 88 D radar. Besides,the signal- to- noise ratio had definite effects on velocity aliasing and velocity dealiasing. The bigger the signal- to- noise ratio was,the higher the accuracy rate of velocity dealiasing was,and vice versa.