Meteosat-12 Lightning Imager: first year of observations and the main performance characteristics

The Meteosat Third Generation (MTG) Lightning Imager (LI) onboard Meteosat-12 satellite is the first geostationary optical lightning detector imaging Europe, Africa, and a large fraction of the Atlantic Ocean. LI detects optical pulses caused by lightning. Optical pulses at cloud tops are produced by the photons emitted by lightning electric discharges within or below clouds that reach cloud tops after multiple scattering. The LI senses this cloud-top light within a 1.9 nm wide band centred on 777 nm, with a 4.5 km resolution at sub-satellite point, and 1 kHz sampling frequency.

LI was declared operational on October 31, 2024. The operationally disseminated LI data consists of point data and accumulated data. The point data products are the lightning groups (LGR) and lightning flashes (LFL), containing the times, latitudes, longitudes and optical radiance information of observed lightning groups and flashes. These allow for near real time monitoring and tracking of storm cells, identifying lightning jumps and building up long-term lightning statistics.  

The three accumulated data products, Accumulated Flashes (AF), Accumulated Flash Area (AFA) and Accumulated Flash Radiance (AFR) provide users with information about the full spatial extent of the observed optical pulses, integrated over 30 seconds. This type of information highlights features like the most active convective cores and long horizontal lightning channels in the stratiform regions of Mesoscale Convective Systems. All accumulated products are provided on the Flexible Combined Imager (FCI) 2 km grid, making it easy to combine LI and FCI products for more advanced severe weather monitoring products.

LI detects 1-3 million flashes and 20-50 million groups per day. EUMETSAT continuously monitors the main performance characteristics of the LI, including Detection Efficiency (DE), Location Accuracy (LA), Timing Accuracy (TA) and Flash False Alarm Rate (FFAR), against external long-range (GLD360) and short-range (EUCLID) lightning location systems. During its first months of operations, LI has shown very high DE (80-90% a), very good location accuracy (5-10 km) and timing accuracy (~1 millisecond), and low FFAR (<0.1 flashes per second). The presentation will showcase LI capability of monitoring lightning from local flash level to hemisphere-scale annual statistics and will give a more detailed overview of the LI performance during its first year of operations.