Satellite will track the steady rise of the oceans

Sentinel-6 Michael Freilich will become the primary means of measuring the shape of the world's oceans.

Its data will track not only sea-level rise but reveal how the great mass of waters are moving around the globe.

It's equipped with a radar altimeter. This instrument sends down a microwave pulse to the surface and then counts the time it takes to receive the return signal, converting this into an elevation.