The Sentinel-6a sea level satellite, launched on Saturday, will continue with unparalleled precision a nearly thirty-year mission whose data are crucial for observing climate change at work in the world’s seas.
The size of a large van, the machine weighing 1.2 tons launched Saturday in space using the American Falcon-9 launcher, from the Californian base of Vandenberg.
Sentinel-6a is the fifth and latest in a line of sea level watchmen, since 1992 and the Franco-American Topex / Poseidon mission, a machine developed by the National Center for Space Studies (CNES) and the Nasa.
Their altimeters have established that over almost thirty years, the average sea level has risen by about 8 cm. A figure seemingly minimal but reflecting major environmental and climatic effects, such as the melting of glaciers and ice floes and global warming. An accelerating increase, worrying for the some 770 million humans living within five meters. above sea level.
To monitor it, Sentinel-6a will be placed at an altitude of 1,336 km, in a polar orbit allowing it to cover 95% of the planet’s oceans in ten days. Its theoretical lifespan is five and a half years. It will be taken over by its clone, Sentinel-6b, in 2025.
“What is very important is to be able to look at the accelerations, the evolutions (of the level of the oceans, editor’s note), to see if certain scenarios of rupture of climate change, which are underway in the Arctic in particular, will go come true, “said Alain Ratier, director of Eumetsat, the European agency for the exploitation of meteorological satellites. It is with its American equivalent, NOAA, one of the partners of the mission.
afp / asch