C波段双偏振雷达降水估计的误差分析与建模  

Error analysis and modeling of C-band dual polarization radar quantitative precipitation estimation

作　　者：唐佳琪 寇蕾蕾[1,2] 蒋银丰 楚志刚[1] 陈爱军[1,2] TANG Jiaqi;KOU Leilei;JIANG Yinfeng;CHU Zhigang;CHEN Aijun(School of Atmospheric Physics,Nanjing University of Information Science and Technology,Nanjing 210044,China;Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学大气物理学院,南京210044 [2]南京信息工程大学气象灾害预警与评估协同创新中心,南京210044

出　　处：《气象学报》2022年第2期224-242,共19页Acta Meteorologica Sinica

基　　金：国家自然科学基金面上基金项目(41975027);国家重点研究发展计划重点专项(2017YFC1501401)。

摘　　要：双线偏振雷达定量降水估计精度受多种因素影响,为了更好地应用双偏振雷达估计降水并进一步提高降雨估测精度,需对雷达降水估计进行误差分析和建模。基于2015—2016年南京信息工程大学C波段双偏振雷达、雨滴谱仪观测资料以及南京地区雨量计数据,统计分析雷达估测降水的误差分布,分离雨量计代表性误差,并对随机误差和系统误差量化建模。首先对双偏振雷达数据进行预处理,并利用雨滴谱仪数据拟合测雨方程,通过对R(ZH)、R(ZH,ZDR)、R(KDP)、R(KDP,ZDR)4个测雨公式反演结果与雨量计对比,分析每个测雨公式在不同降水强度时的估测性能。随后,利用雨量计数据估计空间相关函数,计算并分离由于雷达和雨量计空间不匹配造成的雨量计代表性误差,并分析测量误差和参数误差在雷达降水估计误差中的比重。基于雷达降水估计误差属性及分布规律,建立随机误差和系统误差量化模型。最后,基于4个测雨公式性能和误差分析,提出一种优化组合的双偏振雷达降水估计算法。结果表明,R(ZH)和R(ZH,ZDR)在弱降水时性能较好,当雨强阈值大于2.5 mm/h时,KDP的优势得以突显。由于空间不匹配造成的雨量计代表性误差不容忽视,在雷达分辨单元较大时进行定量降水估计需剔除点面误差。将雷达降水估计误差按照系统误差和随机误差进行建模,发现雷达近地面降水的系统误差和雨强成正比,呈线性函数形式,而双指数模型更好地表示随机误差分布。基于不同雷达测雨公式性能提出的优化组合降水算法在准确度和稳定性等方面优于单个测雨公式。The quantitative precipitation estimation accuracy of dual-polarization radar is affected by many factors. In order to better use dual-polarization radar to estimate precipitation and further improve the rainfall estimate accuracy, error analysis and modeling of radar precipitation estimation are needed. Based on observations of the C-band dual-polarization radar of Nanjing University of Information Science and Technology from 2015 to 2016,raindrop spectrometer observation data and rain gauge data in Nanjing, the error distribution of radar estimation precipitation is statistically analyzed, the gauge representativeness error variance is separated,and the error quantitative model based on random error and systematic error is established. Firstly, the data of dual polarization radar is preprocessed, and the radar rainfall formula is fitted by the data of raindrop spectrograph in the observation base of Nanjing University of Information Science and Technology. By comparing the four radar rainfall formula R(ZH), R(ZH, ZDR), R(KDP), R(KDP,ZDR) with the rain gauge, the estimation performance of each formula under different precipitation thresholds is analyzed. Then, the spatial correlation function of rain gauge data is estimated, the gauge representative error caused by spatial mismatch between radar and rain gauge is calculated, and the proportion of measurement error and parameter error in radar precipitation estimation error is analyzed. Based on the attribute and distribution rule of radar precipitation estimation errors, they are divided into random errors and systematic errors, and a quantitative model is established. Finally, based on the performance and error analysis of four radar rainfall formula, an optimized combination of dual polarization radar precipitation estimation algorithm is proposed. The results show that R(ZH) and R(ZH, ZDR) have better performance for light precipitation estimation. When the rainfall threshold is greater than 2.5 mm/h,the advantage of KDP becomes obvious. The gauge representat

关 键 词：双偏振雷达 性能分析 误差方差分离 误差建模 优化组合 

分 类 号：P412.25[天文地球—大气科学及气象学]