A verification of the lightning detection data from FY-4A LMI as compared with ADTD-2

Abstract

In this paper the match percentage (MP) of lightning frequency in Jiangsu, China from June to August in 2019 is analyzed, by comparing the lightning mapping imager (LMI) data from FengYun (FY)-4A geostationary meteorological satellite with the Advanced Direction and Time-of-arrival Detecting (ADTD)-2 total lightning location data and radar composite reflectivity. The results show that the MP increases with the spatial matching window, yet when the matching window is larger than 0.8° (~80 km), the MP tends to be stable. Furthermore, the spatial distribution of lightning and the characteristics of the match lightning (ML) current are analyzed. The horizontal detection error of LMI for isolated thunderstorm clusters is about 0.15 ± 0.003° (~15 km). The amplitude of the lightning current is an important but not the only factor affecting the satellite's detection efficiency. Through the 10 min analysis of a large-scale and long-term thunderstorm process in Jiangsu province on July 6, 2019, it is found that the lightning detected by LMI and ADTD-2 occurred mostly in the region with strong echoes above 40 dBZ or in its vicinity. With the development of the thunderstorm, the lightning detected by ADTD-2 gradually increased and reached a maximum at 14:40. Subsequently, with the weakening of the thunderstorm system the lightning detected by ADTD-2 gradually decreased. However, the lightning detected by LMI was less all the time before 18:30 and then increased gradually. In the fourth stage (19:40 on July 6–00:20 on July 7), LMI has the highest relative detection efficiency of 12.78%–14.66% using ADTD-2 as a reference, indicating that the satellite detection is relatively less efficient during the daytime.