Sentinel for sea-level rise enters testing

satellite being assembled
Flying under the Copernicus badge secures the programme’s long-term future STEPHANE CORVAJA/ESA

The next satellite tasked with maintaining the “gold standard” measurement of sea-level rise is about to enter final testing

Sentinel-6a will pick up from the long-running Jason series of spacecraft when it launches in November 2020. These missions track the height and shape of Earth’s oceans with microwave altimeters.

Sentinel-6 satellite mock-up in space
Sentinel-6 will launch on a Falcon-9 rocket in November 2020

Since 1992, the orbiting instruments have observed sea level go up by an average of 3.2mm per year. This trend is accelerating, however. The most recent five-year period, from 2014 to 2019, has witnessed a 4.8mm/yr increase.

storm seen from space satellite
Changes in sea-surface height will inform forecasts of storm intensity NASA

Just as air pressure tells meteorologists what is going on in the atmosphere, so ocean height will betray details about the behaviour of water below just the top layers.

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 key elements of our weather and climate systems.


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