26 July 2016
Trying to measure sea levels around rugged coastlines is not always an easy task. ESA’s CryoSat satellite is making a difference with its radar altimeter.
Sea level is a very sensitive indicator of climate change, reflecting components of the climate system such as heat, glaciers and the melting of ice-sheets.
Precisely monitoring changes in the average level of oceans is vitally important for understanding not only climate but also the social and economic consequences of any rise in sea level, especially in coastal zones.
Previous radar altimeters have been aimed at measuring oceans and land, but CryoSat’s is the first sensor of its kind designed for ice, and able to map sea levels with unprecedented accuracy.
Scientists from the Norwegian University of Life Sciences also discovered that CryoSat had the potential to map sea level closer to the coast.
Using satellite altimeters in coastal zones is notoriously difficult. Norway boasts the world’s second longest coastline of some 100 000 km, comprising many islands, steep mountains and deep, narrow fjords.
The rugged coastline means that other altimeters produce confused readings close to the coast, showing differences of 10 cm or more.
By contrast, CryoSat’s results compare favourably with the Stavanger tide gauge in southwestern Norway, provided by the Norwegian Mapping Authority.