摘要
利用云南昭通CC雷达和威宁探空等资料,对贵州省威宁县2017年7月23日的一次冰雹云发展过程的雷达基本反射率因子和径向速度的变化特征进行分析,同时通过插值得到剖面变化特征,研究雹云垂直结构演变,并根据雷达回波顶高、强回波中心(45 dBZ)高度、组合反射率和垂直累积液态水含量(VIL)这4个雷达探测特征物理量,进行时间序列分析,得到防雹作业效果。结果表明:(1)降雹前对流单体的合并使回波强度和VIL分别跃增至60 dBZ和50 kg·m^(-2)以上,冰雹云的雷达回波出现旁瓣回波和“V”形缺口。(2)中低层气流的径向辐合及高层强辐散带来的强烈抽吸作用所产生的上升气流,使雹云能够稳定维持和发展。(3)防雹作业后,雹云开始由上至下分裂直至完全分裂成两个孤立弱单体,回波顶高明显降低,组合反射率较峰值下降近30 dBZ。(4)在作业单元和对比单元的生命史时间内,作业单元的4个雷达探测特征物理量下降速率均大于对比单元的,表明防雹作业有效抑制了雹云的发展。通过对比分析发现,防雹作业24 min后,4个雷达探测特征物理量的双比值均小于1,进一步证明防雹作业取得了明显的正效果,加速了对流单体的消亡。
Using the data from Zhaotong CC radar and Weining sounding station,we analyze the variation characteristics of radar basic reflectivity factor and radial velocity of the developing hail clouds in Weining,Guizhou Province on July 23,2017.At the same time,we investigate its vertical structure evolution of the hail clouds by interpolating to obtain profiles.Then,hail suppression effects are demonstrated after the time series analysis of four characteristic physical quantities of radar detection,that is,the radar echo top height,the 45 dBZ strong echo height,composite reflectivity and vertically integrated liquid water content(VIL).The results show that:(1)The merging of convective cells before the hail shooting increased the radar echo intensity and the VIL to more than 60 dBZ and 50 kg·m^(-2),respectively.The radar echo features of hail clouds such as parabolic echo and V-shaped inflow gap were also captured.(2)The radial convergence of the middle and low-level airflows and the strong suction effect generated by the strong divergence of the upper air produced updrafts,enabling the stable existence and development of hail clouds.(3)After the hail suppression operation,the hail cloud started to split from top to bottom until it completely split into two isolated weak monoliths.The echo top height descended significantly,and the composite reflectivity decreased by nearly 30 dBZ from the peak.(4)Within the life time of the operational unit and the comparison unit,the decrease rate of each of the four radar detecting parameters of the operational unit was faster than that of the comparison unit,indicating that the hail suppression operation effectively suppressed the development of the hail clouds.The double-ratio analysis denotes that the double-ratio values of the four characteristic physical quantities of radar detection were all less than 1 after 24 min,which further proves that the hail suppression achieved a positive effect and expedited the dissipation of hail cloud.
作者
姚展予
赵洁云
屠琦
张泽群
刘臻
王伟健
姚振东
Yao Zhanyu;Zhao Jieyun;Tu Qi;Zhang Zequn;Liu Zhen;Wang Weijian;Yao Zhendong(Chinese Academy of Meteorological Sciences,CMA Cloud-Precipitation Physics and Weather Modification Key Laboratory,Beijing 100081,China;Chengdu University of Information Technology,Chengdu 610225,China;Lianyungang Meteorological Office,Lianyungang 222006,China)
出处
《气象与环境科学》
2024年第4期1-12,共12页
Meteorological and Environmental Sciences
基金
国家自然科学基金项目(42375198)。
关键词
雷达回波
雹云特征
防雹效果
物理检验
radar echo
hail cloud characteristics
hail suppression effect
physical test
