Just two weeks after launch, ESA’s latest Sentinel satellite has offered a taste of the new insights it will provide for the EU’s Copernicus programme. Sentinel-3A will be the first satellite altimeter to provide 100% coverage over all of Earth’s surfaces in synthetic aperture radar (SAR) mode, and will capture valuable observations for monitoring sea level rise.
Sentinel-3A’s very first image (shown above) was captured on 29 February 2016 and shows the transition from day to night over Svalbard, in the Arctic Sea near Norway. As well as showing the snow-covered archipelago, the image also details Arctic sea ice and some cloud features.
The image was captured by the satellite’s ocean and land colour instrument, OLCI. Since it’s first photographs, Sentinel’s radar altimeter for measuring sea height has been busy tracking the changing ocean. The added radar altimeter makes Sentinel-3A the first instrument of the Sentinel program equipped to can track sea-level change.
Just after the radar altimeter instrument was turned on, it traced the height of the sea surface over a stretch of the North Atlantic. The altimeter is designed to deliver accurate measurements of sea-surface height, significant wave height and surface-wind speeds over the world’s oceans for Copernicus ocean forecasting systems and for monitoring sea-level change.
On average, the global sea-level has been rising at a rate of just over 3 mm per year over the last 20 years. However, this figure varies considerably around the world. The Sentinel-3 mission will offer valuable insight into these important variations.
Pierre-Yves Le Traon from Mercator Ocean said these first results are very promising and illustrate the great potential Sentinel-3 has for the Copernicus Marine Environment Monitoring Service. Sea-surface height data from the satellite’s altimeter will, for example, significantly improve the capability to analyse and forecast ocean currents. This is essential for applications such as marine safety, ship routing and predicting the fate of marine pollution events.
The altimeter will also be used to map ‘significant wave height’, which again is important information needed for ship safety. It will also provide accurate topography measurements over sea ice, ice sheets, rivers and lakes.
Sentinel-3A has shown that the first two instruments are working well. Next, we are anticipating the results from its first radiometer acquisition –measuring radiation from Earth’s surface.