FY-4A/LMI闪电与浙江三维闪电对比分析

Comparative Analysis between FY-4A/LMI Lightning Data and Three-Dimensional Lightning Data in Zhejiang Province

为进一步加强星地闪电观测资料运用,本文基于2020年6—8月FY-4A/LMI闪电数据(LMIG)和浙江省ADTD-2C三维闪电定位数据,对比分析两套闪电数据的时空分布特征,并结合雷达和云顶亮温资料,分析了2020年7月15日浙江省雷暴过程两套闪电观测资料的演变规律。结果表明:2010年6—8月,浙江省LMIG与三维闪电比值为1∶44.43;两套资料闪电月分布和空间分布总体一致;就日分布而言,LMIG呈现双峰结构,三维闪电则为单峰结构。两套数据时间匹配窗口大于1.8 s、经纬度匹配窗口大于0.5°时,匹配率趋于稳定;与LMIG匹配的三维闪电高度主要集中在16 km以下,闪电强度主要集中在50 kA以下。2020年7月15日浙江省午后雷暴天气,LMIG与三维闪电比值为1∶25.44;LMIG首次闪电及峰值时间均滞后于三维闪电首次闪电及峰值时间;此外两套闪电资料时间演变与雷暴发展有较好的对应,空间变化与云顶亮温低值区也有较好的对应。

In order to further strengthen the application of satellite-to-ground lightning,the spatial-temporal distribution characteristics and spatial-temporal matching features are comparatively analysed in Zhejiang Province based on lightning data from FengYun(FY)-4A Lightning Mapping Imager(LMI)and Advanced Direction and Time-of-arrival Detecting(ADTD)-2C three-dimensional lightning location system from June to August in 2020.In addition,by combining reflectivity of Doppler radar mosaics and cloud top brightness temperature from FY-4A Advanced Geosynchronous Radiation Imager(AGRI),the spatial and temporal evolution patterns of lightning data from two observation systems are analysed during a thunderstorm process in Zhejiang Province on 15 July 2020.The results show that from June to August in 2020,the number of LMIG detected by LMI was 8483,while the number of lightning detected by the ADTD-2C three-dimensional lightning location system was 376932.The ratio of the two sets of data was approximately 1∶44.43.The monthly and spatial distributions of lightning detected by these two systems were generally consistent,while diurnal variation of which were different.Specifically,diurnal variation of LMIG presented two peaks,and diurnal variation of three-dimensional lightning showed only one peak.Besides,when the time matching window was larger than 1.8 seconds,and the latitude and longitude matching window was larger than 0.5°,the matching rate gradually tended to be stable.Furthermore,the height of three-dimensional lightning matched with LMIG was mainly concentrated below 16 km,and the lightning intensity of which was mainly concentrated below 50 kA.During the thunderstorm weather in Zhejiang Province in the afternoon on 15 July 2020,the ratio of LMIG to three-dimensional lightning was approximately 1∶25.44.The time of the first LMIG and its peak time were both later than the time of the first three-dimensional lightning and its peak time.What’s more,the lightning data observed by the two systems corresponded well with the development process of the thunderstorm.When the thunderstorm was at the developing stage,the number of lightning data detected by the two systems was both gradually increasing,and when the thunderstorm was at the mature stage,the number of lightning data detected by the two systems was both maintaining a relatively high value,and when the thunderstorms were at the dissipation stage,the number of lightning data detected by the two systems was both decreasing rapidly.When it came to the spatial distribution of the lightning,both of the two datasets corresponded well with the spatial distribution of low cloud top brightness temperature.