星地探测闪电在一次中尺度对流系统中的活动特征分析

Analysis of Activity Characteristics of Satellite-to-Ground Lightning Detection in A Mesoscale Convective System

为更好地发挥星地闪电探测资料在中尺度对流系统中的监测预警应用潜力,本文以2018年6月27日山东地区的一次中尺度对流系统为例,利用云顶温度、云顶降温率、雷达等资料与FY-4A闪电成像仪LMI(Lightning Mapping Imager)、ADTD(Advanced TOA and Direction system)闪电定位系统星地闪电探测资料,分析了星地闪电数据在中尺度对流系统中闪电分布特征及其与对流演变的关系,结果表明:星地探测闪电一致性较好,LMI相对位于对流云前方,星地闪电与降水区域吻合度较高。在系统发展初期,LMI超前于ADTD探测到闪电,且位于回波中心和前侧,回波垂直方向呈现出向前倾斜特征,这对于判识对流移动和演变趋势有较好的指示作用,在预报业务中可采用LMI的位置来辅助制作强对流落区预报。在成熟阶段,星地闪电频次出现跃增,正地闪比例较高,该时段山东多地发生冰雹灾害,LMI多出现在对流系统移动方向前方的弱回波或无回波区内,ADTD则更接近回波中心位置。合并阶段,部分LMI位于前方强回波区后部,与强回波区相对应。

In order to better exert the monitoring and early warning application potential of satellite-to-ground lightning detection data in the Mesoscale Convective System(MCS),this study takes an MCS in Shandong on June 27,2018,as a case,using the cloud top temperature,cooling rate,the reflectivity from radar and the satellite-to-ground lightning data from FY-4A Lightning Mapping Imager(LMI)and Advanced TOA and Direction system(ADTD)to analyze the lightning distribution characteristics and its relationship with the evolution of convection.The results show a good consistence of the satellite-to-ground lightning data.The lighting of LMI was further located in front of the convective cloud and had a high agreement with the precipitation region.In the early development stage of MSC,LMI detected lightning earlier than ADTD,and the lightning was located in the centre and the front side of the radar echo.The vertical section of the echo showed a forward tilting,which was a good indicator of the movement and evolution trend of convection.Thus,the location of the lightning from LMI could be used to assist in the forecast of strong convection areas.In the mature stage,the frequency of satellite-to-ground lightning increased,and the proportion of positive ground lightning was relatively large.Hail disasters occurred in many places in Shandong Province during this period.The LMI mostly appeared in the weak or no-echo area in front of the moving direction of the convective system,while the ADTD lightning was closer to the centre position of the echo.During the merging stage,some of the LMI lightning was located at the backside of the front,strong echo area corresponding to the strong echo area.