Lightning

Lightning observation from space addresses where and how often lightning flashes occur, whether a storm is intensifying, whether a fire-igniting flash is likely and whether a grid asset is exposed. Lightning can occur within a cloud, between clouds or between cloud and ground; cloud-to-ground lightning is about 25 percent of all lightning ^[1]. Most ground-based sensors detect only cloud-to-ground lightning, whereas space-based sensors measure all forms over land and sea around the clock ^[1]. This topic covers space-borne observation; ground lightning networks, which locate cloud-to-ground strokes to within a few hundred metres, are context only ^[2].

Current geostationary sensors are narrowband optical cameras at 777.4 nm ^[3][4][5]. The Geostationary Lightning Mapper (GLM) on the National Oceanic and Atmospheric Administration (NOAA) Geostationary Operational Environmental Satellite (GOES) series has pixels of 8 km at nadir and 14 km at the edge of the field of view, covers the Americas and nearby ocean up to 52 degrees north, and delivers products with 20 second latency; NOAA states 70 to 90 percent flash detection day and night ^[3]. For GOES-16 GLM against a lightning mapping array in central Florida, mean daily flash detection efficiency was 73.8 percent, with 20 to 40 percent for small short flashes ^[6]. GLM flies on GOES-18 (GOES West) and GOES-19 (GOES East) as of June 2025 ^[7]. As of a NOAA notice of 24 August 2026, GOES-19 GLM products have been degraded since 17 July 2026 by additional false flashes, mainly in the tropics between 1500 and 1900 UTC, after a safehold event on 15 July with no end date given ^[8].

The Meteosat Third Generation Lightning Imager (MTG LI) has provided data since late 2024 over about 84 percent of the visible Earth disc, covering Europe, Africa, the Middle East and parts of South America ^[9]. Pixels are 4.5 km at the sub-satellite point ^[4]. An assessment against ground networks and GLM from July 2024 to December 2025 found flash detection efficiency from 70 percent by day to 95 percent at night, averaging 87.4 percent ^[10]. The Lightning Mapping Imager (LMI) of the China Meteorological Administration flies on Fengyun-4 (FY-4) satellites at 7.8 km resolution ^[11][5]. FY-4A observes China from spring to autumn and the Indian Ocean and western Australia otherwise ^[11].

In low Earth orbit, the Optical Transient Detector launched in April 1995 with 10 km resolution and 40 to 65 percent detection efficiency ^[12]. The Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) operated from 1997 to April 2015, and a spare LIS on the International Space Station (ISS) operated from 2017, with decommissioning planned by the end of 2023 ^[13]. GLM, MTG LI and LMI observe from geostationary orbit, each over a regional sector rather than the whole globe ^[3][9][11].

For climate use, the Global Climate Observing System (GCOS) lists lightning as an essential climate variable and a possible indicator of storminess trends ^[14]. Satellite records come from separate sensors with a gap of about two years between 2015 and 2017 ^[13]. ISS LIS global flash rates ran 5 to 10 percent below earlier datasets, attributed mainly to lower detection efficiency ^[15].

For warnings, rapid increases in lightning often precede severe and tornadic storms, and GLM products update every 20 to 60 seconds against roughly 5 minutes for radar ^[7][3]. GLM data help route flights around storms over oceans without radar ^[16]. In boreal North America lightning explained over 55 percent of year to year variation in burned area ^[17], and flashes with continuing current longer than 10 ms show higher ignition probability than cloud-to-ground lightning in the contiguous United States ^[18].