Sentinel-6: 'Dog kennel' satellite to measure sea-level rise

A satellite that will be critical to understanding of climate change will launch on Saturday from California.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.Looking somewhat like a dog kennel, the sophisticated 1.3-tonne satellite is due to lift off from the Vandenberg base at 09:17 local time (17:17 GMT).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.OneWeb satellite company is officially rebornNew Sentinels to check the pulse of EarthDams played key role in limiting sea level riseAbout half of the measured global sea-level rise on Earth is from warming waters and thermal expansion, a key driver of which is global warming. The other half is coming from melting ice.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 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.Why is ocean height so important?Elevation is a key parameter for oceanographers. Just as surface air pressure reveals what the atmosphere is doing above, so ocean height will betray details about the behaviour of water down below.The data gives clues to temperature and salinity. When combined with gravity information, it will also indicate current direction and speed.The oceans store vast amounts of heat from the Sun; and how they move that energy around the globe and interact with the atmosphere are what drive our climate system.But having the longest possible record of change is essential."The longer that time series, the better able we are to separate out the natural climate signals from the forced ones, from the human signal," explained European Space Agency mission scientist Craig Donlon."It means we can run climate models backwards and then, through a validation process, have confidence that when we run them forwards we have some predictive skill."