US and European scientists are about to get a unique view of polar ice as their respective space agencies line up two satellites in the sky. Authorisation was given on Tuesday for Europe’s Cryosat-2 spacecraft to raise its orbit by just under one kilometre. This will hugely increase the number of coincident observations it can make with the Americans’ Icesat-2 mission.
One outcome from this new strategy will be the first ever reliable maps of Antarctic sea-ice thickness. Currently, the floes in the far south befuddle efforts to measure their vertical dimension. Heavy snow can pile on top of the floating ice, hiding its true thickness. Indeed, significant loading can even push Antarctic sea-ice under the water.
But researchers believe the different instruments on the two satellites working in tandem can help them tease apart this complexity. Nasa’s Icesat-2, which orbits the globe at about 500km in altitude, uses a laser to measure the distance to the Earth’s surface – and hence the height of objects. This light beam reflects directly off the top of the snow. Esa’s Cryosat-2, on the other hand, at around 720km in altitude, uses radar as its height tool, and this penetrates much more deeply into the snow cover before bouncing back.
Source: BBC
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