基于云雷达和降水雷达资料的一次典型暖云降水成因及粒子类型演变  

Formation and hydrometeor type evolution of a typical warm precipitation based on cloud radar and precipitation radar data

作　　者：陈梓桐 李昀英 CHEN Zitong;LI Yunying(College of Meteorology and Oceanography,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学气象海洋学院,湖南长沙410073

出　　处：《大气科学学报》2022年第1期87-98,共12页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(42075077);国家重点研发计划项目(2018YFC1507604)。

摘　　要：针对2020年8月9日南京市一次典型对流性暖云降水过程,结合云雷达和双偏振降水雷达资料,研究了此次短时强降水的雷达回波特征和成因;基于雷达参量和模糊逻辑算法识别了水凝物粒子类型,并分析了降水过程中水凝物粒子的性质和演变。结果表明:此次降水强度大、效率高,雷达观测的云体回波呈现低质心、强回波的热带型结构。正负速度对的出现表明云体中存在较强的涡旋辐合场,谱宽和线性退极化偏比数值偏大,云体中上部存在强上升气流区,这些可表征短时强降水即将发生。模糊逻辑算法识别的降水粒子以雨滴为主,云体顶部主要分布干、湿雪粒子。降水机制主要是云体中云粒子和降水粒子数目多,直径差别较大,取向复杂,在上升气流和涡旋辐合场作用下剧烈碰并增长成大雨滴而发生短时强降水。Research of particles from cloud to rain is a fundamental approach to study the precipitation mechanism.Based on the cloud radar and dual-polarization precipitation radar data,this paper analyzes the echo characteristics and formation of a typical convective warm cloud precipitation process in Nanjing on August 9,2020.Using various radar parameters and fuzzy logic algorithm to identify the hydrometeor types,the evolution of hydrometeors in precipitation process is analyzed.Results show that the cloud with high precipitation efficiency behaves approximately a tropical structure with strong and low echo centricity.When the radar observes large spectrum width and linear depolarization ratio,strong updraft in the upper cloud and positive-negative velocity presenting vortex convergence,it indicates that heavy precipitation is about to occur.The precipitation particles identified by the fuzzy logic algorithm are mainly raindrops,with wet and dry snow particles at the top of the cloud.With a large number of cloud and precipitation particles in different sizes and complex orientations,the collision-coalescence process,as the main precipitation mechanism,is quickly completed under the action of the rising air flow and vortex convergence.

关 键 词：暖云降水 模糊逻辑算法 水凝物粒子类型 

分 类 号：P412.25[天文地球—大气科学及气象学]