After six months of in-orbit verification and calibration, the Sentinel-6 Michael Freilich satellite will make its first two data streams available to the public on June 22. It was launched from Vandenberg Air Force Base in California on November 21, 2020. and is a U.S.-European collaboration to measure sea surface height and other key ocean characteristics, such as wind speed at the ocean surface and wave height.
One of the sea surface height data streams that will be released is accurate to 2.3 inches (5.8 centimeters) and will be available within hours of instrument collection aboard Sentinel-6 Michael Freilich. A second data stream, accurate to 1.4 inches (3.5 centimeters), will be released two days after collection. The difference between when products become available balances accuracy with speed of delivery for tasks like forecasting the weather and monitoring hurricane formation. Further datasets, which will be accurate to about 1.2 inches (2.9 centimeters), are expected to be distributed later this year and are intended for research activities and climate science, including monitoring the rise in global mean sea level.
The satellite, named after former director of NASA’s Earth Sciences division Michael Freilich, collects its measurements for about 90% of the world’s oceans. It is one of the two satellites that make up the Copernicus Sentinel-6 / Jason-CS (Continuity of Service) mission. The second satellite, Sentinel-6B, is expected to launch in 2025. Together, they are the latest in a series of spacecraft starting with TOPEX / Poseidon in 1992 and continuing with the Jason series of satellites which collect precise measurements of the height of the ocean for almost 30 years.
Shortly after launch, Sentinel-6 Michael Freilich moved into position, trailing the current sea-level reference satellite Jason-3 by 30 seconds. Scientists and engineers then spent time cross-calibrating the data collected by the two satellites to ensure continuity of measurements between the two. Once they are assured of the quality of the data, Sentinel-6 Michael Freilich will then become the primary satellite at sea level.
“It’s a relief to know the satellite is working and the data is good,” said Josh Willis, project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “In a few months, Sentinel-6 Michael Freilich will replace his predecessor, Jason-3, and this data release is the first step in that process. “
Keeping an eye on the rising seas
The ocean absorbs over 90% of the heat trapped in the Earth’s system by increasing greenhouse gas concentrations, causing seawater to expand and sea level to rise. Monitoring the height of the oceans is important because it helps forecasters predict things, including ocean currents and the potential strength of hurricanes.
“This initial data shows that Sentinel-6 Michael Freilich is an amazing new tool that will help improve marine and weather forecasting,” said Eric Leuliette, program and project scientist at the National Oceanic and Atmospheric Administration in Maryland. “In a changing climate, it is a great achievement that this data is ready for publication. “
The head of the ocean altimetry program, Julia Figa Saldana of EUMETSAT (European Organization for the Exploitation of Meteorological Satellites), added that the operational dissemination of the first data streams from this unique ocean altimetry mission was an important step. at the start of the hurricane season in the Atlantic.
“The elevation data is now processed at EUMESAT’s headquarters in Darmstadt, from where the satellite is also monitored, and disseminated to users of ocean and weather forecast data around the world for their operational use,” said Saldana.
Scientists also plan to use the data to assess how quickly sea level is rising due to climate change. Expansion of warm seawater accounts for about a third of modern sea level rise, while meltwater from glaciers and ice caps accounts for the rest. The rate of ocean rise has accelerated over the past two decades, and researchers expect it to accelerate further in the years to come. Rising sea levels will change coasts and increase flooding caused by tides and storms. To better understand the impact of rising seas on humanity, researchers need long climate records, which Sentinel-6 Michael Freilich will help provide.
Learn more about the mission
Sentinel-6 / Jason-CS is jointly developed by ESA (European Space Agency), EUMETSAT, NASA and NOAA, with financial support from the European Commission and technical support from the French National Center for Space Studies.
JPL, a division of Caltech in Pasadena, provides three scientific instruments for each Sentinel-6 satellite: the Advanced Microwave Radiometer, the Global Navigation Satellite System — Radio Occultation, and the Laser Retroreflector Array. NASA also provides launch services, ground-based systems supporting the operation of NASA’s scientific instruments, scientific data processors for two of these instruments, and support for US members of the International Scientific Topography Team of the surface of the oceans.
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