NASA launches U.S.-European satellite to track sea level rise
https://www.nbcnews.com/science/space/n ... e-n1248519
NASA launches U.S.-European satellite to track sea level rise
The Sentinel-6 Michael Freilich satellite, put into Earth orbit, is expected to have unprecedented accuracy.
Nov. 21, 2020, 1:01 PM MST
By The Associated Press
VANDENBERG AIR FORCE BASE, Calif. — A U.S.-European satellite designed to extend a decades-long measurement of global sea surface heights was launched into Earth orbit from California on Saturday.
A SpaceX Falcon 9 rocket carrying the satellite blasted off from Vandenberg Air Force Base at 9:17 a.m. and arced southward over the Pacific Ocean. The Falcon’s first stage flew back to the launch site and landed for reuse.
The Sentinel-6 Michael Freilich satellite was released from the second stage about an hour later. It then deployed its solar panels and made first contact with controllers.
Named for a former NASA official who had a key role in developing space-based oceanography, the satellite’s main instrument is an extremely accurate radar altimeter that will bounce energy off the sea surface as it sweeps over Earth’s oceans. An identical twin, Sentinel-6B, will be launched in 2025 to ensure continuity of the record.
Space-based sea level measurements have been uninterrupted since the 1992 launch of the U.S.-French satellite TOPEX-Poseidon, which was followed by a series of satellites including the current Jason-3.
Sea surface heights are affected by heating and cooling of water, allowing scientist to use the altimeter data to detect such weather-influencing conditions as the warm El Nino and the cool La Nina.
The measurements are also important for understanding overall sea level rise due to global warming that scientists warn is a risk to the world’s coastlines and billions of people.
“Our Earth is a system of intricately connected dynamics between land, ocean, ice, atmosphere and also of course our human communities, and that system is changing,” Karen St. Germain, NASA’s Earth Science Division director, said in a pre-launch briefing Friday.
The new satellite is expected to have unprecedented accuracy.
“This is an extremely important parameter for climate monitoring,” Josef Aschbacher, the European Space Agency’s director of Earth observation, told The Associated Press this week.
“We know that sea level is rising,” Aschbacher said. The big question is, by how much, how quickly.
Other instruments on board will measure how radio signals pass through the atmosphere, providing data on atmospheric temperature and humidity that can help improve global weather forecasts.
Europe and the United States are sharing the $1.1 billion (900 million euro) cost of the mission, which includes the twin satellite.
What's wrong with putting a graduated post at the high tide mark?
PP
NASA launches U.S.-European satellite to track sea level rise
- Undried Plum
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Re: NASA launches U.S.-European satellite to track sea level rise
One of the problems with using tide gauges to measure global sea level rise is that the land itself is going up and down at differing rates in different parts of the world.
TOPEX-Poseidon and the rest are able to measure the seal level itself, independent of any land mass.
TOPEX-Poseidon and the rest are able to measure the seal level itself, independent of any land mass.
Re: NASA launches U.S.-European satellite to track sea level rise
Relative to what datum?Undried Plum wrote: ↑Sun Nov 22, 2020 9:38 pmTOPEX-Poseidon and the rest are able to measure the sea level itself, independent of any land mass.
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Re: NASA launches U.S.-European satellite to track sea level rise
WGS84.
That's the spheroid to which they relate the geoid. Actual sea level is then related to the deduced geoid.
Land upheaval, either positive or negative is then calculated by taking the sea surface as datum at tide gauges instead of the other way around which had been the practice for two or three hundred years.
That's the spheroid to which they relate the geoid. Actual sea level is then related to the deduced geoid.
Land upheaval, either positive or negative is then calculated by taking the sea surface as datum at tide gauges instead of the other way around which had been the practice for two or three hundred years.