Lightning Climatology Datasets from TRMM LIS, ISS LIS, and OTD

Abstract New gridded lightning climatology datasets are compiled and released from a series of low-Earth-orbiting NASA lightning sensors: the Optical Transient Detector (OTD), Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS), and International Space Station (ISS) LIS. OTD collected data during April 1995–March 2000, TRMM LIS collected data during December 1997–April 2015, and ISS LIS collected data during March 2017–November 2023. From these, gridded lightning datasets depict the near-global distribution of annual-mean flash rate on a 0.1° grid. Hourly mean and monthly mean averages allow examination of diurnal and annual cycles, although some smoothing of the released data is warranted. This paper describes the released datasets, thoroughly examines data quality and sources of bias, and makes recommendations for potential users. Examples from these datasets are shown, with well-known lightning hotspots in central Africa, northwestern South America, and along the base of the Himalayas. Comparison of how often thunderstorms are observed to those storms’ conditional mean flash rates shows some striking differences, with frequent storms but relatively low per-storm flash rates over the Maritime Continent. Conversely, storms are less frequent but produce higher flash rates over central North America, subtropical South America, Pakistan, and the coasts of northern Australia.