Coastal cities could be regularly under water, hurricanes and storm surges could increase their destructive power and island paradises sink into the sea: The rise in sea level is one of the greatest threats that climate change brings with it. The Intergovernmental Panel on Climate Change (IPCC) assumes that with unchecked climate change it could be more than a meter by the end of the century. This is likely to be a problem not only for the Maldives in the Indian Ocean, whose highest point is just over two meters. The coasts of Europe are also in danger.

In order to measure and map the rise in sea level, scientists want to use a new earth observation satellite from the Looking at the oceans in space – more precisely than ever before. Sentinel-6 Michael Freilich scans within ten days 90 percent of the global ocean surface – from a height of more than 1300 Kilometers with an accuracy of less than one millimeter.

Measurement of the sea level with millimeter accuracy Earth observation satellites have been around for decades. “But Sentinel 6 has a new radar on board, with a higher precision, which will be able to measure a rise in sea level even more precisely,” says the director for earth observation programs at the European space agency ESA, Josef Aschbacher. As part of the European Earth observation program Copernicus, the satellite will be controlled from Darmstadt by a new, ultra-modern control center of the European meteorological satellite agency, Eumetsat, says the head of the program at the Darmstadt satellite specialists, Manfred Lugert.

Many experts had to pull together to make the spacecraft a reality. The mission is a cooperation between ESA, the US space agency NASA, Eumetsats and the US weather and oceanography agency NOAA. The satellite is the first of two identical satellites to be launched into space. It is named after the recently deceased Michael H. Freilich, the former director of NASA’s Earth Observation Department.

The satellite should initially be on 10. Launch from Vandenberg Air Force Base, California, on November 11th. Now the start is delayed a little because the engines of the launcher have to be checked again. A new date was not initially set. The second, identical satellite is to follow in five and a half years. According to Aschbacher, the entire project cost those involved in the USA and Europe around 400 million euros.

The Radar pulses from the satellite are transmitted, reflected by the sea surface and received again. “Nobody can do anything with the data at first. That has to be converted into high-precision distance measurement,” says Lugert. “The exact determination of the location in orbit is the great challenge of the mission.” Wave heights would have to be resolved and atmospheric influences would have to be factored out in distance measurements. There are two independent navigation systems on board for determining the location, and the satellite orbit is regularly measured with a laser. According to Aschbacher, in conjunction with other satellites, conclusions can be drawn about the density and thickness of the ice. This is important, for example the melting of the Greenland ice has tripled since the 90 years.

The Sentinel-6 Michael Freilich Earth observation satellite is being refueled.

(Source: ESA ) Precise picture of the situation “We now get a global dimension every ten days, so a picture like that Location is, “says Aschbacher. “The satellite provides data that has not been available so precisely before.” As a state-of-the-art and high-precision component, it will complement the monitoring of the planet from space. “There are certainly some 100 satellites that are currently in orbit and monitoring the earth,” says Aschbacher. The Europeans are in the lead here because the system covers everything – from science to weather forecasts to civil protection.

“But there is still a lot to be done,” Aschbacher is certain. There are still parameters that need to be measured more precisely. “One of the greatest challenges is the more accurate measurement of the greenhouse gas carbon dioxide.” It is still not precise and comprehensive enough. For the future, he would like to see a satellite system that measures all of these parameters. The data could then be linked and coupled with artificial intelligence. This makes it possible to make real predictions and simulations around the system earth, for example how high the sea level rise will be in different temperature scenarios.

( olb)