郴州天气雷达估测降水量误差分析

Analysis of Precipitation Estimation Deviation of Synoptic Radar in Chenzhou

新一代天气雷达系统使用Z-I关系式反演降水,在估测降雨时不同地域具有不同误差;在观测降水时受到水平阵风或短时大风、回波强度、地形、大气折射等因素影响,可能降低雷达定量估测降水的精度。本文利用湖南郴州雷达基数据不同低仰角反射率因子分别估算出降水量,对比分析了不同仰角雷达反演估测降水量与自动雨量站雨量数据之间的误差。通过对雷达估测降水的误差来源分析、估测降水误差并应用数学统计分析误差,初步得出:2.4°仰角估测降水与雨量站的观测数据线性相关系数最高,雷达估测的降水较为真实。而0.5°、1.5°仰角受地型影响估测降水可行性不高。

The new-generation weather radar system uses the Z I relation to invert the precipitation.Different deviations emerge in different regions.During the observation of precipitation,the accuracy of quantitative estimation of precipitation may be weakened due to the influence of horizontal gusts,shortterm strong winds,echo intensity,topography,atmospheric refraction,and other factors.In this study,the precipitation is estimated by using the reflectance factor at different elevation angles of the radar basic data and the deviations between the estimated precipitation by radar inversion at different elevation angles and the rainfall data of automatic meteorological stations are compared and analyzed.According to the analysis of the deviation sources of estimated precipitation of radar and the precipitation deviation estimates,using mathematical statistics methods,it is concluded:the 2.4°estimates of precipitation own the highest linear correlation coefficient with automatic station observation and the radar estimation of precipitation in this angle is more real,and the 0.5°and 1.5°estimations affected by the topography are not applicable.