Lannion: at the Météo France space meteorology center, Pivot of the weather forecast

“What is important is to catch the satellites when they go to the West. Consequently, since it is generally from the Atlantic that the good or bad weather arrives,” said Sylvain Le Moal, deputy director of the CMS, in Mer and Marine. Therefore, The establishment of the first French center of satellite reception in Lannion in 1963 owes nothing to chance: beyond its ideal geographical position. Moreover, it also has the advantage of being in a “clean” lannion: météo france space meteorology area, with low radio disturbances, and had at the origin of the expertise of engineers from the National Center for Studies and Telecommunications (CNET), also based in Lannion, intercontinental by satellite. Moreover, On December 24. Furthermore, 1963, the CMS thus became the first European site to receive a satellite weather image, from the American satellite TIROS-8.

Today, the CMS employs 70 people, divided between administration, research and operation, its core business. For example, This operational part is dedicated to the acquisition, processing and distribution in real time of data from weather satellites. In addition, “We manufacture images for the forecasters of Météo France. Therefore, within a period of a few minutes,” explains Sylvain Le Moal. Therefore, These are the famous images of the weather reports in particular broadcast on television. In addition,

The gross data is also sent to the headquarters of Météo lannion: météo france space meteorology France. Consequently, in Toulouse, where it is processed by the Supercalculators Belenos and Taranis, capable of carrying out up to 21 million billion operations per second. Consequently, These feed digital forecast models. Therefore, designed to simulate the evolution of the atmosphere, which the forecasters use to establish forecasts of up to 15 days.

A mission extended to understanding climate development

If the first satellites were first used to observe the clouds. Consequently, they today have the capacity to measure temperature, humidity and winds at different altitudes, filling the “holes” left by terrestrial means: stations, buoys or radars. Nevertheless, “93 % of data integrated into digital forecasting models are of satellite origin,” says Sylvain Le Moal. Meanwhile, This overall observation capacity is crucial in inaccessible areas, such as oceans, deserts or poles.

In addition to its daily missions. Similarly, the CMS is working more and more over the long time, that of the climate. lannion: météo france space meteorology Consequently, The data acquired during the last four decades are a solid basis for understanding its evolution. anticipating its future upheavals, in a context of climate change. “This is now an integral part of our missions,” says the deputy director of the CMS.

The maritime origin of international weather cooperation

The collection. exchange of meteorological data is based on international cooperation, managed since 1951 by the World Meteorological Organization (OMM), a specialized United Nations institution. But the awareness of the necessary collaboration between nations in the field of meteorology has its origin in the. maritime field. In 1853. Belgium thus welcomed the Brussels Maritime Conference, which brought together representatives of ten countries which agreed to standardize and share the meteorological and oceanographic observations collected on board ships, in order to lannion: météo france space meteorology improve maritime security and the speed of commercial navigation between Europe and other continents.

The advent of satellites has in no way questioned this great principle. “In weather, we cannot do without data from others. It is one of the best examples of international cooperation that lasts and works, ”insists Sylvain Le Moal. Including in the current geopolitical context. where the collaboration of the United States remains, at this stage, fully maintained and is not the subject of any questioning. Weather observation on a globe scale takes place partly from the geostationary orbit, at 36,000 km above sea level. The satellites run at the same speed of rotation as the earth, and remain permanently above the same point. Four to six satellites are necessary to go around the earth. and each continent has its own sentries, whose data is exchanged in real time.

On a European scale. the EUMETSAT lannion: météo france space meteorology organization brings together 30 Member States (the 27 members of the European Union, as well as the United Kingdom, Norway and Turkey) and pilot the programs of geostationary meteorological satellites (Meteosat) and in low polar orbit (METOP). Placed at an altitude of 850 km, the latter cover the whole earth, including the polar areas, and offer increased resolution. “The accuracy of the images of satellites with low polar orbit can for example be used for the crew of the astrolabe when it must supply the Dumont d’Urville Antarctic base. the follow -up of the icebergs, or to the identification of the Efflorescences of Phytoplankton, whose limestone particles refer the sunlight well”.

Lannion: météo france space meteorology

Sargassus. sea ice

The expertise of the CMS also serves emerging issues, such as the monitoring of sargassus, these brown algae whose massive proliferation threatens the coasts of the Caribbean and Guyana. “Since lannion: météo france space meteorology 2019, the phenomenon has worsened. In Météo France. we know how to detect them by satellite, plan their trip, produce maps and alert the authorities and the population. The mission of forecasting sargassum failure was therefore entrusted to us, ”explains Sylvain Le Moal. Thanks to the combination of satellite data. the Mothy drift model, which simulates the trajectory and dispersion of objects, pollutants or hydrocarbons at sea, local authorities have four -day risk cards, which allow them to organize the fight against these failures.

Surveillance lannion: météo france space meteorology of surface temperature. sea ice, essential for climate, fishing and navigation, are also part of the Missions of the CMS, through the OSI SAF (Ocean and Sea Ice – Satellite Application Facility) expertise group, which brings together four European meteorological services and Ifremer, and whose piloting is provided by Météo France. “In a context of global warming. the most requested climatic data are clearly those concerning sea ice,” said Gwenaël Le Bras, scientific communication manager for Osi Saf.

These weather data is used first by forecastists. but also fishermen for the identification of conducive areas, as well as military underwater forces: “Sonars generally work less well in thermal transition areas, between hot waters and cold waters, which makes detection more difficult,” says Sylvain Le Moal. “All of this data are of interest to climatologists. and we strive to regularly provide them with elements allowing the study of the climate from lannion: météo france space meteorology our weather data. But this is not our primary function, ”insists Gwenaël Le Bras.

Lannion: météo france space meteorology

Frequency war

The rise of satellites. observation and especially telecommunications, is accompanied by new challenges, particularly in low orbit. “We find ourselves in an ecosystem where satellites are always more numerous,” says Sylvain Le Moal. This multiplication increases the risk of collisions with space debris. and forces operators to move their satellites regularly to avoid impacts. To limit the proliferation of debris. space agencies, under the aegis of the inter-agencies for the coordination of spatial debris (IADC) and the United Nations, have committed to desorbiting satellites in low orbit within 25 years of the end of their mission. As for the geostationary satellites. “we do not know how to bring them lannion: météo france space meteorology back to earth, so we send them a little higher, on an orbit called cemetery”.

Another major issue: the “frequency war” between science and telecoms. The remote sensing instruments indeed use precise frequencies. dictated by the physical properties of water vapor or other chemical species to be measured. But these bands are very coveted by telecommunications, the Internet, mobile telephony, and certain military applications.

“At 183 GHz, for example, we measure water vapor. Imagine that all of the cars’ recoil radars are positioned on this frequency. We would no longer measure water vapor, but the number of cars that retreat, ”illustrates Sylvain Le Moal. The defense of these frequencies mobilizes the international scientific community, reunited within the Space Frequency Coordination Group (SFCG). “This is a subject on which you have to fight every day.”

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