Lightning ring signatures with the Meteosat Lightning Imager (MTG-LI) compared to the Lightning Mapping Array in northeastern Spain

Launched into geostationary orbit in December 2022, the first Meteosat Third Generation satellite contains the Lightning Imager, which started delivering data operationally since July 4th, 2024, monitoring lightning over Africa, Europe, western parts of the Middle East and eastern South America with a fixed angular resolution pixel size, equivalent to 4.5 km footprint size at nadir.

During initial analysis of cases during 2023 and 2024, experts of the European Severe Storms Laboratory (ESSL), EUMETSAT and the lightning research community noted differences in the evolution of LI flash rates compared to GLD360, and sometimes the LI detections sometimes took the shape of a ring around the core of active, hail producing storm cells.

The question arose if such ring is indeed a "lightning hole" as previously identified in supercells using 3D lightning mapping arrays (LMA) collocated with mesocyclones, or is instead an artifact of the optical detection, caused by high cloud ice or graupel concentration in the upper part of the storm cloud, combined with the weaker light emission from small lightning flashes.

We compare the presence of LI lightning rings to the presence of LMA lightning holes and properties of flashes using data of 2024 and 2025. LI flash rates are compared to LMA flash rates using different thresholds of LMA flash size. Additionally, we show examples of the correspondence between LI and LMA detection of leader processes within individual lightning flashes.

The Lightning Mapping Array in northeastern Spain is a joint network operated by the Universitat Politècnica de Catalunya (AEI grant EQC2021-006957-P) and the Meteorological Service of Catalonia, each operating 15 stations and real-time processing server. It is currently the largest LMA in the world, detecting lightning activity in a circle about 600 km in diameter.