C波段双偏振多普勒天气雷达资料分析及在定量估计降水中的应用研究

基于南京信息工程大学C波段双线偏振多普勒天气雷达(NUIST-CDP)的观测资料，结合南京龙王山SA天气雷达数据、南京信息工程大学大气综合观测基地的OTT Parsivel雨滴谱仪数据、南京市地面雨量计数据，分析NUIST-CDP探测资料的质量及定量降水估计(QPE)精度情况。将NUIST-CDP与SA雷达的回波强度数据进行了对比，发现NUIST-CDP回波强度偏弱；将滴谱仪上方NUIST-CDP测量的反射率因子Z_H、差分反射率因子Z_DR与滴谱仪数据对比，雷达参量Z_H、Z_DR与滴谱仪数据变化趋势一致，但整体略偏小；比较差分传播相移率K_DP与Z_H的变化情况，由差分传播相移Φ_DP经最小二乘法计算得到的K_DP与Z_H数据一致性很好。利用南京地区2015年夏季(5—8月)收集的滴谱数据计算偏振雷达参数，拟合测雨方程，进行两次降水过程个例的QPE分析，并与南京地区雨量计数据进行了对比。结果表明:R(K_DP)测雨精度最高，R(K_DP，Z_DR)次之，使用偏振参量能明显提高降雨估算精度；R(Z_H)、R(Z_H，Z_DR)方法测雨反演结果低于地面雨量计雨量值，且低于SA雷达反演结果。 

C-BAND DUAL-POLARIZATION DOPPLER WEATHER RADAR DATA ANALYSIS AND ITS APPLICATION IN QUANTITATIVE PRECIPITATION ESTIMATION

Based on observation data of two precipitation events in Nanjing on July 2015, the data quality of a C-band dual-linear polarimetric weather radar in Nanjing University of Information Science and Technology (NUSIT-CDP) and its capability of quantitative precipitation estimation (QPE) are presented, using the data from an SA weather radar on Longwang Mountain in Nanjing, an OTT Parsivel disdrometer at a NUIST student observing station, and rain gauges of Nanjing. Compared with the data from the SA radar, the reflectivity factor Z_H of NUIST-CDP is smaller due to attenuation. The data of Z_H and differential reflectivity Z_DR observed by NUIST-CDP, in contrast with the data from the disdrometer, agree well as a whole but are slightly smaller. In addition, the variation trends of Z_DR and K_DP are consistent with that of Z_H, which can effectively present the characteristics of precipitation particles. By using raindrop size distribution data of Nanjing in the summer of 2015 from OTT Parsival, the rainfall estimation equations are fitted, and the validity of the rainfall estimation are tested by comparing the rainfall retrieving results with the rain gauge data. The findings show that the rain rate estimated from R(K_DP) is most accurate and R(Z_H, Z_DR) is less accurate, which means that using dual polarization parameters can improve the rainfall estimation. The rain rate estimated from R (Z_H) and R (Z_H, Z_DR) of the C-band radar are much less than the rain gauge result, and less than the results retrieved with the SA radar.