不同校准方法检验雷达定量估测降水的效果对比

应用雷达低仰角基本反射率资料和地面加密自动站降水量资料,采用最优化方法,根据天津地区降水特点和不同降水类型,建立适用本地的雷达Z-I关系。经实际应用检验,积混降水类型Z-I关系具实用性。在天津本地化Z-I关系基础上,通过了对比分析6种不同校准方法在天津夏季降水估测中的检验效果。结果表明：Z-I关系校准法和最大集成法对降水的估测偏高,误差较大;最优插值法的估测精度最高,平均绝对误差和均方根误差最小;但计算不同校准方法与实况相关性表明,变分校准法的估测效果与雨量计降水量的相关性最好。同时,所有估测校准法对小雨量级的降水均出现了不同程度的偏高估测。

Comparison on quantitative estimation of precipitation using radar based on different calibration methods

Based on the observational data from the low-elevation angle radar and precipitation data from intensive automatic weather station,the local Z-I relationships were established by an optimization method according to precipitation feature and the different precipitation types.According to application test,the Z-I relationship of the cumulus clouds mixed precipitation type is more applicable.The results of precipitation estimated using six calibration methods were compared after the Z-I relationships have been modified specifically for Tianjin area.The results indicate that the errors from both the Z-I relationship calibration method and the maximum integrated method are large;they both overestimate rainfall.The estimation accuracy of the optimal interpolation method is the highest among the all methods,and its mean absolute error and root-mean-square error are the smallest.The correlation coefficient between the estimated rainfall from different methods and the observed rainfall are calculated,and it shows that the correlation between the estimated rainfall of variational calibration method and rain gauge rainfall is significant.To some extent,the rainfall is overestimated to light rain grade among the all methods.