Lightning Mapping Imager

LMI is a geostationary optical lightning mapping imager for detecting and measuring lightning flashes at the 777.4 nm oxygen band. It uses CCD imaging to count lightning flashes and measure intensity, supporting convective precipitation proxy, NOx generation proxy, and Earth electric-field study applications ^[1]. The optical detection approach captures cloud, cloud-cloud, and cloud-ground lightning events through a planar CCD array and imaging sector ^[2]. The instrument specification includes a 400 x 600 CCD-unit array, 500 frames per second image rate, 777.4 nm central wavelength, 7.8 km spatial resolution, and a 4.98 by 7.41 degree total field angle ^[2]. FY-4A operations use seasonal regional sectors, observing China in spring-autumn seasons and the Indian Ocean / western Australia during the rest of the year, while FY-4C uses full-disk mode ^[2]. The instrument is demonstrated for orbital optical detection of lightning transients on FY-4A ^[1].