Illustration: ESA

Climate research boosted with a new European super satellite

Monday 14 May 18


Ole Baltazar Andersen
DTU Space
+45 45 25 97 54

The Sentinel satellites

DTU Space is an active participant in ESA’s Sentinel project. The first Sentinel satellite was launched into space in 2014 with seven satellites orbiting the Earth so far.

A further five are planned for launch in the coming years. They are all part of the comprehensive European environmental and climate monitoring programme Copernicus which is run by ESA and is one of the most ambitious projects of its kind on the planet.

The satellites work in pairs, providing better coverage and more frequent overflights of the same areas and thus more accurate data. They can, among other things, monitor rises in sea levels, sea temperatures, marine pollution in the form of chlorophyll development, the development of storm surges, as well as the propagation and change of vegetation on land and the development of forest fires.

Researchers at DTU are conducting comprehensive climate, environmental, and marine research using data from ESA’s Sentinel satellites. With a new launch, a large part of a very precise system is now complete.

ESA’s Sentinel 3B satellite was recently launched into space from Plesetsk in Russia. Together with its ‘twin’ Sentinel 3A and a number of other Sentinel satellites, the new satellite constitutes an advanced tool for examining the Earth’s environment and climate much more precisely and systematically, e.g. sea temperatures, sea surface heights, sea ice, and marine pollution.

This is something DTU Space will benefit greatly from as it boosts the overall space-based research and monitoring of oceans, the climate, and the environment that a number of research groups at DTU are involved in based on, among other things, data from the Sentinel satellites.

“Both precision and resolution are much higher than previously with this generation of technology,” says Ole Baltazar Andersen, Senior Researcher at DTU Space.

Sentinel 3B is equipped with four advanced instruments. They need to obtain data both for climate research purposes, for example in rises in sea levels and for real time use for investigating the development of storm surges, among other things.

“One of the benefits is that we will now get more precise and frequent height data close to the coast, which is key to DTU’s work of supporting storm surge alert systems,” says Ole Baltazar Andersen.

Precision important close to the coast
By using the two ‘twin’ satellites together, much better data is obtained than previously. The time and spatial coverage of sea height and temperature doubles. The height of the sea surface is measured every two weeks and ocean temperatures around every three days.

Another advantage of the new technology is that sea heights can be measured very close to the coast. This can help determine current and wave conditions around port areas. Earlier space-based technology could not make precise measurements closer than 10 km the coast.

“We expect to be able to predict current, wave conditions, and water depths very precisely close to shore, and such data can, for example, be included in the information systems available when large ships enter ports,” says Ole Baltazar Andersen.

"We will get access to a number of new interesting metrics."
Ole Baltazar Andersen

In addition to using data from the satellites for research and monitoring, DTU Space also participates in the process of calibrating and validating the new satellite to ensure that it delivers accurate data.

Complete Sentinel system in operation
With the launch of Sentinel 3B, a large part of ESA’s Sentinel system is complete.

Combined the satellites cover the Earth and the oceans using, among other things, the SAR radar technology, thermal recordings, optical images, as well as the OLCI instrument on Sentinel 3B, which by detecting colour differences can examine marine pollution.

“We will get access to a number of new interesting metrics,” says Ole Baltazar Andersen.

The new measurements are also compared with data recorded using older satellite technology. This ensures an unbroken chain of comparative measurements that date back more than 25 years, which is important when small changes are to be measured accurately over time. For example, it is a question of measuring rises in sea levels, which are just a few millimetres a year.