Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) Missions, 1995-2023

Année de publication

2026

Lightning flash rate densities measured by a series of low-Earth-orbiting NASA lightning sensors are used to explore lightning hotspots, how they vary with time of year and time of day, the diurnal cycle, annual cycle, and interannual variability. New gridded datasets are available from the Optical Transient Detector (OTD; April 1995-March 2000), Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS; January 1998-April 2015), and International Space Station (ISS) LIS (March 2017-November 2023). Taking all these lightning measurements together, the highest 0.1° flash rate densities are over Lake Maracaibo in northern Venezuela, as reported previously. Other locations emerge as having the highest flash rate densities when limited to smaller subsets of the data. Maxima are located on either side of the Democratic Republic of Congo according to ISS LIS (maximum in the west) and OTD (maximum in the east). ISS LIS also records higher values over mountain slopes in Colombia than over nearby Lake Maracaibo. Summertime flash rate densities are almost as high over northern Pakistan. At the peak of the diurnal and annual cycles, July afternoons over Cuba have almost as much lightning as late nights in September over Lake Maracaibo. Flash rates peak around 1600-1700 LST and gradually decrease through the evening over most continental regions and peak in the summer with little lightning measured during winter. Time series of flash rates show Africa contributing most to the interannual variability, particularly with the sharp downturn in lightning from mid-2019 through 2022. Significance Statement Lightning data from three NASA missions beginning in 1995 and finishing in 2023 enable a variety of analyses. From the full dataset, lightning maxima are noted in northwestern South America and central Africa. The particular location with the most lightning depends on which period of time is examined and how large an area is considered. Lightning peaks in the late afternoon in summer for most places over land. Summer afternoon flash rate densities over Cuba, Florida, and western Mexico rival the peak activity in South America and Africa, but for shorter periods of time. Many regions, especially Africa, had below-normal flash rates from mid-2019 through 2022. Year-to-year variability in the near-global flash rates is largely driven by variability in Africa.</div>

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