Copernicus satellite to monitor sea-level rise launched
The Copernicus Sentinel-6 Michael Freilich satellite has been launched into orbit around Earth. Using radar altimetry, this new satellite is set to provide a new overview of ocean topography and advance the long-term record of sea-surface height measurements that began in 1992 – measurements that are essential for climate science, for policy-making and for protecting the lives of millions at risk of sea-level rise.
Now in orbit, the satellite will soon pick up the baton and extend this dataset. The mission comprises two identical satellites launched sequentially – so in five years, Copernicus Sentinel-6B will be launched to take over. The mission as a whole will ensure the continuity of data until at least 2030.
Orbiting at an altitude of over 1300 km and reaching 66°N and 66°S, Sentinel-6 provides sufficient measurements to map the height of the sea surface over 95% of the world’s ice-free oceans every 10 days.
Each satellite carries a radar altimeter, which works by measuring the time it takes for radar pulses to travel to Earth’s surface and back again to the satellite. Combined with precise satellite location data, altimetry measurements yield the height of the sea surface. The Sentinel-6 instrument package also includes a microwave radiometer that accounts for the amount of water vapour in atmosphere, which affects the speed of the altimeter’s radar pulses.
While heritage has been key to the mission’s design, Sentinel-6 introduces synthetic aperture radar into the altimetry reference mission time series. To mitigate bias being introduced into the time series, the radar instrument operates in a continuous burst mode, simultaneously providing conventional low-resolution mode measurements and the improved performance of synthetic aperture radar processing. To ensure that the data time series is continuous despite the change of instrument technologies, the satellite will spend its first year in orbit flying just 30 seconds behind Jason-3.
While Sentinel-6 is one of the European Union’s family of Copernicus missions, its implementation is the result of a unique cooperation between the European Commission ESA, Eumetsat, NASA and NOAA, with contribution from the CNES French space agency.