多种波长雷达数据一致性分析

Consistency Analysis of Multi-wavelength Radar Data

利用'华南季风降水试验'联合观测资料,对比了Ka波段云雷达和C波段连续波雷达对非降水云和降水云宏观结构的观测结果,定量对比了Ka波段云雷达、C波段连续波雷达、Ku波段微降水雷达和雨滴谱仪的探测回波强度和径向速度,对比分析了Ka波段云雷达和Ku波段微降水雷达云-降水的功率谱密度数据,得到了如下结论:(1) Ka波段云雷达和C波段连续波雷达对不同类型云的探测结果在回波整体的形状、高度及随时间演变上是一致的,云雷达对云的探测灵敏度要略高,对云边缘、云底和云顶的弱回波探测能力更强,但云雷达探测积云和降水云时稍微回波强中心偏弱,两部雷达探测的径向速度和谱宽较为一致;(2)弱降水条件下,Ku波段微降水雷达探测的回波强度较雨滴谱仪偏弱,但偏弱的最大平均误差在-2. 84d BZ,微降水雷达的探测结果基本可靠;(3)弱降水条件下,云雷达和连续波雷达探测的回波强度较微降水雷达分别偏弱4. 81 d BZ和3. 01 d BZ,三者回波强度统计的相关系数分别为0. 842、0. 887和0. 920 (Ka-Ku,C-Ku,Ka-C),在考虑衰减、雷达采样体积差异、雷达灵敏度和天线积水等因素后认为3种雷达回波强度探测结果均较为可靠;(4)微降水雷达探测的径向速度分别比云雷达和连续波雷达偏小0. 59m/s和1. 02m/s,统计的相关系数分别为0. 835、0. 690和0. 9442 (Ku-Ka,Ku-C,Ka-C),云雷达和连续波雷达探测的结果较为一致,造成微降水雷达径向速度偏小的原因与多普勒速度谱偏移和多普勒速度谱速度模糊现象有关。

By using the joint observation dataset from SCMREX(South China Monsoon Rainfall Experiment)and 3 th TIPEX(the third Tibetan Plateau Science Experiment),a comparison of macroscopical features of different kinds of cloud is made by utilizing CR(Ka-band cloud radar)and CWR(C-band frequency modulated continuous wave radar)data,quantitative contrasts of the reflectivity and mean Doppler velocity data observed by the CR,CWR,MMR(Ku-band micro rain radar),and RC(raindroplet collector)are done as a key work,Doppler spectra comparison and analysis of the CR and MRR are performed also under the weak cloud and precipitation conditions.The major conclusions include:1)Observation results of different kinds of cloud detected by CR and CWR show that the overall echoes are similar to each other at the echo shape,height and time-varying.However,CR is more sensitive to the cloud edge,base and top,but echo intensity could be weaker than CWR at the strong center of cumulus and rainfall,the Doppler velocity and spectrum width are approximate to CWR.2)Under weak precipitation condition,the echo intensity of MRR are little weaker than RC,the mean bias is-2.84 d BZ,so,MRR observation results are think to be reliable when considering the instrument’s working principle and systematic deviation.3)Statistical reflectivities of CR and CWR are both weaker than MRR respectively at-4.81 dBz and 3.01 dBZ under slight precipitation,statistical correlation coefficients of each other are 0.842,0.887 and 0.920(MRR-CR,CWR-MRR,CR-CWR),three radars detection results are considered to be reliable when taking into account attenuation,sample volume difference,radar sensitivity and water on the antenna.4)Statistical Doppler velocities of MRR are smaller than CR and CWR respectively at 0.59 m/s and 1.02 m/s under weak rain,statistical correlation coefficients of each other are 0.835,0.690 and 0.9442(MRR-CR,MRR-CWR,CR-CWR),the results of CR and CWR are close,the MRR biases are associated with Doppler spectra shifting and portion of velocity bins getting ambiguous.