A satellite that will be critical to the understanding of climate change has blasted skyward from California, reports BBC.
Sentinel-6 "Michael Freilich" is set to 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 is moving around the globe.
Looking somewhat like a dog kennel, the sophisticated 1.3-tonne satellite was taken aloft from the Vandenberg base on a SpaceX Falcon-9 rocket.
The Sentinel is a joint endeavour between Europe and the US, and will continue the measurements that have been made by a succession of spacecraft, called the Jason-Topex/Poseidon series, going back to 1992.
These earlier missions have shown unequivocally that sea levels globally are rising, at a rate in excess of 3mm per year over the 28-year period. And their most recent data even suggests there is an acceleration under way, with levels recorded as going up at over 4mm per year.
About one-third of the measured global sea-level rise on Earth is from the expansion of warming water, a key driver of which is climate change. The rest is largely from melting ice. Sentinel-6, like all the satellites before it, will use a radar altimeter to assess the height of the oceans. 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.
Sentinel-6 will, however, fly with a much improved capability, which will allow it to see more clearly what seas are doing right up against coastlines; and also how inland water features - rivers and lakes - are behaving.