Sentinel-3

Contribution to operational oceanography continues to expand

Citizens and decision-makers require accurate information about the state of the global oceans, says EUMETSAT Remote Sensing Scientist Hans Bonekamp

People and industries concerned with marine safety, shipping, fisheries and aquaculture, marine pollution and coastal development rely on accurate information about the state of the Earth’s oceans and seas.

Operational oceanography is about delivering reliable and accurate information to citizens and decision-makers on the state of the global oceans.  Because the oceans are difficult to observe in situ, observations from space play a crucial role.

From 2016, EUMETSAT’s contribution to the development of operational oceanography will continue to expand.

EUMETSAT, in cooperation with the European Space Agency, has been tasked by the European Union with exploiting the Copernicus Sentinel-3 ocean monitoring mission and the future Sentinel-6/Jason-CS ocean altimetry mission. In addition, EUMETSAT will also deliver data to Copernicus from the Jason-3 ocean altimetry satellite and from its own and third party missions.

The main objectives of the Sentinel-3 marine mission are to monitor ocean colour, sea surface temperature and ocean surface topography. Sentinel-3’s ocean surface topography measurements will be cross-calibrated against those of Jason-3, which will be the reference altimeter mission until after 2020, when Sentinel-6/Jason-CS will take over as the altimeter reference mission.

"For oceanography, Sentinel-3 is perhaps the most beautiful satellite ever built"

EUMETSAT will control and operate the twin Sentinel-3 satellites, with support from ESA, and deliver its marine mission in synergy with its own missions, providing access to a unique, integrated marine data stream to all service providers and users in the EU and EUMETSAT Member States.

“For oceanography, Sentinel-3 is perhaps the most beautiful satellite ever built,” EUMETSAT Remote Sensing Scientist and altimetry expert, Hans Bonekamp, said.

“That is because Sentinel-3 has really been designed for ocean applications, for the co-registration of sea surface temperature, ocean colour and height measurements.

“We will have two Sentinels flying together, and have the follow up with Sentinels-3C and -3D, so we really could see the same measurements for 15 to 20 years, which is very important for oceanography, to deal with the very long time scales.”

Bonekamp said it was critical to have altimeters on board a number of satellites – Jason, Sentinel and Chinese and Indian spacecraft – to ensure accurate measurements of the oceans.

Altimeters are used to measure sea surface height. By cross-validating measurements from the altimeters onboard different satellite missions, an accurate picture of sea surface height can be obtained, providing information for ocean forecasting models and monitoring mean sea level rise.

“Sentinel-3 is, of course, not the only altimeter mission.  As well as having an altimeter on Sentinel-3 and Jason-3, we will have sea surface temperature measurements from the EUMETSAT Metop and Meteosat satellites, and also data from third party missions such as SUOMI NPP,” Bonekamp said.

“This is a very important aspect for the science and the service we bring to the users.  Because by having these different measurements we can understand where the discrepancies are and explain the differences to the users.

"Sentinel-3 is the next step for EUMETSAT in terms of enlarging its involvement in satellite altimetry"

“From the users’ perspective, we need to have the multi-mission perspective and Sentinel-3 will be a major player in the constellation.”

Ocean altimetry data are also used to map the variability of ocean currents. Like stronger winds are associated with low pressure in the atmosphere, stronger currents are associated with sea surface elevation, Bonekamp said. 

The ocean currents transport a lot of heat from the tropics to the poles, so the information derived from the altimeter measurements is crucial for ocean modellers and researchers of sea level rise.

“Altimeters also measure wind speed and significant wave height and this is needed by the wave communities, particularly for marine safety,” Bonekamp said.

Operational oceanography is relatively recent, when compared to meteorology, and therefore there is still a lot to be done in the scientific realm, which is a challenge for operational mission use.

“Sentinel-3 is the next step for EUMETSAT in terms of enlarging its involvement in satellite altimetry and now to not only do Near Real Time services but also climate services,” Bonekamp said.

“I’ve been working on the Sentinel-3 project for five or six years.  A lot of work has gone in to it.

“It’s a very complex system – the instruments are very complex.  To integrate the scientific developments very quickly into the operational setting is a challenge.

“The scientists are now doing a lot of meetings, planning and organisation.  (After the launch) we will go back to analysing the data and seeing what the measurements look like.  I’m looking forward to that.”

Last Updated:  Monday, 15 February 2016