Meteosat Third Generation: connect images, lightning and soundings

Meteosat Third Generation, or MTG, uses imaging and sounding spacecraft with different payloads. The first imager launched in December 2022 and became Meteosat 12. The first sounder, MTG-S1, launched in July 2025. The complete system design combines two imagers and a sounder; that design should not be mistaken for a claim that every planned spacecraft is already operational.

Imagers follow cloud and surface patterns and detect lightning. Sounders provide information about the atmosphere’s vertical temperature and moisture structure. The sounder spacecraft also hosts Copernicus Sentinel-4, a separate instrument concerned with atmospheric composition. Sharing a platform does not merge the weather sounder and Sentinel-4 into one measurement.

The Flexible Combined Imager has sixteen visible and infrared channels. Its design supports ten-minute full-disc scans and faster regional scanning. The Lightning Imager detects optical pulses from lightning, including activity within clouds as well as flashes between clouds and the ground. A lightning observation adds information that an ordinary cloud image does not supply.

Infrared sounding uses spectral measurements to estimate atmospheric structure. A changing temperature and moisture profile can help assess conditions in which clouds and storms may develop. These retrieved profiles are not photographs of stacked atmospheric layers. Their usefulness depends on spectral sensitivity, processing and the conditions under which the observation was acquired.

MTG: complementary spacecraft

In a fictional developing-storm case, compare the evolving cloud pattern, available soundings and lightning activity. Each observation contributes a different clue. A new lightning signal does not by itself specify the future track, rainfall total or local impact. Forecasters combine satellite products with other observations and models to evaluate the developing situation.

Nowcasting — open definition focuses on current conditions and the very near future, where frequent updates are especially useful. MTG was designed to strengthen that work while extending the longer Meteosat record. Improvements must be assessed through validated products and forecast performance, not assumed from a newer generation number. Keep design capabilities, launched hardware and operational product availability distinct when describing the program.