Sentinel-6 satellite: Watching the sea level rise
New offspring for the Copernicus family! The Earth observation satellite Sentinel-6 is scheduled to be launched on November 21. Its superpower: Sentinel-6 can monitor the ocean with millimeter precision.
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The Earth observation satellite is intended to measure our oceans and chart the sea level. And this is likely to be a rather depressing sight from space. After all, it is no secret that the sea level is tending to rise with growing rapidity. While it increased by only 2 centimeters (0.79 inches) in the entire 18th century, it already went up by 6 centimeters in the 19th century and a whole 19 centimeters in the 20th. Industrialization and human-made global warming certainly have had something to do with this.
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Sentinel-6 is the first of two identical satellites that are to be launched into space. Sentinel-6B, the twin satellite, is scheduled for launch in 2025. The two satellites are meant to collect data for at least five years.
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It will scan 95% of the global sea surface within 10 days — from an altitude of more than 1,300 kilometers (800 miles) and to an accuracy of less than 1 millimeter.
In addition, it is also to collect precise data on atmospheric temperature and humidity, which can help improve weather forecasts and climate models.
The satellite sends out radar impulses that are reflected from the sea surface and then received again by the spacecraft. "Nobody can do anything with this data at first. It has to be converted into a high-precision distance measurement," says Manfred Lugert, head of Copernicus Mission Development and Jason-CS/ Sentinel 6 program manager at EUMETSAT. He said wave heights and atmospheric influences would also have to be taken into account when measuring distances.
Two independent navigation systems are also on board for determining the location. The satellite's orbit is regularly measured with a laser.
By working together with other satellites, Sentinel-6 will also help to make inferences about the density and thickness of ice. This is important, says Josef Aschbacher, ESA's director for Earth observation programs. The Greenland ice sheet is currently melting at three times the rate in the 1990s, he says. "We will now get a global measurement every 10 days — in other words, a picture of what the momentary situation is like," says Aschbacher. "The satellite will provide data that has not been available in this detail before."
What's so special about Sentinel-6?
Earth observation satellites as such have been around for decades — for example, TIROS-1, the first experimental weather satellite, was launched on April 1, 1960.
The Copernicus Earth Observation Program launched the Sentinel-1A satellite on April 3, 2014, followed by 1B on April 25, 2016. Since then, other types of Sentinel satellites have been added.
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The Sentinel-1 satellites provide detailed radar images of the planet's surface in all types of weather, day and night. Sentinel-2's specialty is to detect changes in vegetation and do things like provide crop forecasts, chart forests and monitor the growth of wild and agricultural plants. Sentinel-3 provides temperature measurements of land and ocean.
Sentinel-4, whose launch is planned for 2022, will collect data on the concentration of pollutants in the air. Sentinel-5 is a mission to measure atmospheric gases worldwide. Sentinel-5P analyzes the composition of the atmosphere.
But Aschbacher says there is still a lot to be done and still parameters that need to be measured more accurately. For example, he says, the greenhouse gas carbon dioxide is still not being measured precisely and comprehensively enough.
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https://www.dw.com/en/sentinel-6-satellite-watching-the-sea-level-rise/a-55659812
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