Several billion euros and twelve years of preparation to scrounge up a few precious hours in predicting severe weather phenomena: Europe is preparing to launch the first of its new generation weather satellites. The 3.8 tonne beast sits in a white room at Thales Alenia Space in Cannes before taking the boat to Kourou, where it is to be launched by the end of the year.
Once in orbit at 36,000 km altitude, MTG-I1, for Meteosat third generation-imager, will scan the planet every 10 minutes with an accuracy of up to 500 meters, half as much as the previous generation launched at early 2000s. It is to be followed by 2025 by a twin (MTG-I2), which will focus on Europe at the rate of one scan every two and a half minutes, and a satellite equipped a probe (MTG-S) which will analyze the composition of the atmosphere over its entire height.
Three other similar satellites must succeed them at the end of their lifespan, 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 operating these satellites for twenty years. A massive investment justified by the fact that no weather report is possible today without these space sentinels.
Follow the rapid evolution of convective phenomena
“More than 95% of the 40 million observations made each day for weather forecasts come from satellites,” recalls Simonetta Cheli, director of Earth observation programs at the European Space Agency (ESA).
And “with the exponential growth of extreme weather events”, she recalls, the images must be more and more precise and frequent. The challenge is to detect the rapid evolution of convective phenomena, the movements of the atmosphere at the origin of thunderstorms and storms. The thunderstorms accompanied by gusts of more than 200 km/h which hit Corsica on August 18, killing five people, come from a rapid accumulation of water vapor in the atmosphere on a very localized surface, and “this type local change can be detected very quickly by MTG,” explains Donny Aminou, Satellite Payload Manager for ESA.
“We have a lot of expectations on monitoring the development of convective clouds, we hope to gain a few hours of notice”, crucial for alerting populations, abounds Hervé Roquet, deputy director of research at Météo-France.
A “wink from 10 kilometers”
The satellite carries another valuable instrument in the eyes of meteorologists: a lightning detector, a 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 Italian Leonardo. Some of the lightning is currently spotted by Earth systems, but those that streak through clouds without touching the ground were not. However, they can be precursors of devastating storms.
MTG’s sensors will also better detect forest fires and particles in the atmosphere. The closure of air traffic such as that which occurred over a large region due to the ash scattered by the eruption of an Icelandic volcano in 2010 could thus be avoided from now on, according to its designers.
“Now, meteorologists only have to digest the data,” laughs Pierre Armand, program manager for Thales Alenia Space. The volume of data sent to Earth promises to be colossal: 110 megabits per second every day, 50 times more than the previous generation. They will also be used to develop new weather forecasting and climate change models.