Europe launches its new generation of weather satellites

Once in orbit at an altitude of 36,000 kilometers, MTG-I1, for Meteosat’s third-generation imaging camera, will scan the planet every 10 minutes with an accuracy of up to 500 meters, half as much as the previous generation launched from the early 2000s.

4.3 billion euros in total

It should be followed by 2025 by a twin (MTG-I2), which will focus on Europa at a rate of one scan every two and a half minutes, and a satellite equipped with a probe (MTG-S), which will analyze the composition of the atmosphere over its entire height. Three other similar satellites, already under construction, were to succeed them at the end of their lifetime, of at least eight and a half years.

In total, this program, launched in 2010, represents a budget of 4.3 billion euros, divided between ESA and Eumetsat, the organization responsible for the operation of these satellites for 20 years.

A massive investment justified by the fact that no weather forecast is possible today without these space watchers. “More than 95% of the 40 million observations made every day for weather forecasting come from satellites,” recalls Simonetta Cheli, Director of Earth Observation Programs at the European Space Agency (ESA).

Anticipate rapid changes

And “with the exponential growth of extreme weather events,” she recalls, the images must be increasingly accurate and frequent. The challenge: to detect the rapid development of convective phenomena, the movements of the atmosphere at the origin of thunderstorms and storms.

The thunderstorms accompanied by wind gusts of more than 200 km/h, which hit Corsica on August 18 and killed five people, come from a rapid accumulation of water vapor in the atmosphere on a very localized surface, and “this type of local change can be detected very quickly by MTG,” explains Donny Aminou, Satellite Payload Manager for ESA.

“We have a lot of expectations to monitor the development of convective clouds, we hope to have a few hours’ notice”, which is essential to warn populations, says Hervé Roquet, deputy director of research at Météo France.

detect lightning

The satellite carries another valuable instrument in the eyes of meteorologists: a lightning detector, the first in Europe.

Equipped with four cameras, it can “distinguish the equivalent of the blink of an eye at 10 kilometers” day and night, according to Carlo Simoncelli, program manager at Italy’s Leonardo.

Some of the lightning is currently detected by ground-based systems, but those that sweep the clouds without touching the ground are much more numerous and were not. However, these can be precursors to devastating storms, according to Mr. Roquet, which also emphasizes a breakthrough for aviation security.

Forest fires and fine particles

MTG’s sensors will also better detect forest fires and particles in the atmosphere. The closure of air traffic like the one that happened over a large region due to the ash scattered by the eruption of an Icelandic volcano in 2010 could thus, according to its designers, be avoided from now on.

“Now the meteorologists just have to digest the data,” laughs Pierre Armand, program manager for Thales Alenia Space, the industrial prime contractor.

The amount of data sent to Earth promises to be colossal: 110 megabits per second (Mbps) every day, 50 times more than the previous generation. They will also be used to develop new weather forecasting and climate change models.

At the same time, Europe is preparing the next generation of Metop satellites. These two weather satellites in low orbit, at an altitude of a few hundred kilometers, are complementary to geostationary satellites such as MTG. Used for 10-day forecasts, Metops takes higher-quality images of the entire Earth’s surface, but only passes over the same area on a daily basis.

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