Effects of Day/Night Factor on the Detection Performance of FY4A Lightning Mapping Imager in Hainan, China

In this study, the effect of day/night factor on detection performance FY4A lightning mapping imager (LMI) is evaluated using Bayesian theorem, and by comparing it to measurements made a ground-based low-frequency magnetic field location system. Both datasets were collected in summers 2019–2020 Hainan, China. The results show that for observed summer thunderstorms daytime efficiencies LMI (DELMI) 20.41~35.53% lower than nighttime DELMI. Compared other space-based sensors (lightning imaging sensors/optical transient detectors (LIS/OTD) geostationary mapper (GLM)), more significantly influenced factor. DELMI rapidly dropped within about four hours after sunrise while increased before sunset. For storms formed at night lasted an entire day, remained relatively low during daytime, even as intensified. poor probably because sunlight reflection clouds atmosphere, which larger background radiative energy density (RED) night. During night, captured signals well with RED (8.38~10.63 μJ sr−1 m−2 nm−1). However, less 77.12 nm−1 filtered, thus groups could rarely be identified LMI, except those extremely high RED. Due limitations obtained DE study was “relative” rather “absolute” DE. To obtain absolute total necessary but can hardly measured. Nonetheless, shown here clearly indicate strong impact used improve design post-processing method LMI.