C-FMCW雷达反演飑线大气垂直速度和雨滴谱  

Retrieval of Air Vertical Velocity and Droplet Size Distribution in Squall Line Precipitation Using C-FMCW Radar

作　　者：陈绍婕 郑佳锋[1,2] 杨吉 车玉章 任涛 黄轩 Chen Shaojie;Zheng Jiafeng;Yang Ji;Che Yuzhang;Ren Tao;Huang Xuan(School of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225;Key Laboratory of Transportation Meteorology,China Meteorological Administration,Nanjing 210008;Nanjing Joint Institute for Atmospheric Sciences,Nanjing 210041)

机构地区：[1]成都信息工程大学大气科学学院,成都610225 [2]中国气象局交通气象重点开放实验室,南京210008 [3]南京气象科技创新研究院,南京210041

出　　处：《应用气象学报》2022年第4期429-441,共13页Journal of Applied Meteorological Science

基　　金：国家重点研发计划(2018YFC1507005);江苏省气象科学研究所北极阁基金项目(BJG201901);成都信息工程大学人才引进项目(KYTZ201728)。

摘　　要：垂直指向探测的C波段调频连续波雷达具有高灵敏度和高时空分辨率等特点,以2016年5月广东两次飑线降水为例,结合同址K波段微雨雷达和地面激光雨滴谱仪,探究C波段调频连续波雷达两种反演大气垂直速度(V_(a))和雨滴谱的方法:粒子平均下落末速度(V_(t))-反射率因子(Z_(e))关系法(简称经验关系法)和小粒子示踪法(简称示踪法)。结果表明:经验关系法和示踪法反演的上升和下沉气流的时空分布基本一致;当地面雨强R≤1 mm·h^(-1),经验关系法反演的雨滴谱与雨滴谱仪观测结果更接近;当1<R≤10 mm·h^(-1)时,两种方法反演的雨滴谱均与雨滴谱仪观测及微雨雷达产品较吻合;当R>10 mm·h^(-1)时,两种方法反演的中雨滴数浓度与雨滴谱仪观测结果接近,但大雨滴数浓度较低;从各物理量时序变化看,经验关系法反演结果更接近雨滴谱仪观测结果。The zenith C-band frequency modulation continuous wave(C-FMCW)radar has good detection capability with high temporary-spatial resolution and large dynamic range.The Doppler spectral density data of two squall lines precipitation cases at Longmen of Guangdong are utilized to retrieve the air vertical velocity(V_(a))in clouds and droplet size distribution(DSD).The empirical relation method(checking relationship between mean particle falling velocity(V_(t))and reflectivity factor)and the small-particle-trace method are explored to retrieve the air vertical velocity in clouds.And then the droplet size distribution is retrieved from the translated Doppler spectral density by a velocity-diameter relation.The retrieved DSD of two squall lines are then compared and validated with the observation of K-band micro rain radar and secondgeneration Parsivel disdrometer.The retrieved V_(a) by the empirical relation method is slightly smaller for strong monomer than that by the small-particle-trace method and slightly larger for weak convective precipitation,but V_(t) is the opposite.The absolute value of V_(t) negative velocity by the empirical relation method and the small-particle-trace method corresponds to the moment of large particles and heavy rain observed by Parsivel disdrometer,indicating that V_(a) of two methods is basically reliable.The comparison in DSD retrieval show that the number of small droplets observed by radar is higher,but Parsivel disdrometer may underestimate it.The results of the empirical relation method are closer to micro rain radar and Parsivel disdrometer when rain rate is below 1 mm·h^(-1).The medium droplets obtained by radar retrieval are consistent with Parsivel disdrometer measurements,but the concentration of large droplets is low when rain rate is stronger than 10 mm·h^(-1).The retrieval results of both methods are close to Parsivel disdrometer and micro rain radar when rain rate is between 1 mm·h^(-1) and 10 mm·h^(-1).The strong convection makes droplets rupture severer in the peak are

关 键 词：C-FMCW雷达 功率谱 大气垂直速度 雨滴谱分布 

分 类 号：P412.25[天文地球—大气科学及气象学]