In 2010, the European Space Agency launched Cryosat, a spacecraft designed to monitor changes in the shape and thickness of polar ice on Earth. It's taken the scientists behind the project some time to crunch through all the data — but they've managed it, and the new images offer an unprecedented view of the state of our ice caps.
While there have been previous satellite measurements of how quickly ice is disappearing, Cryosat is the first to be able to measure the volume of ice in great detail — which is crucial in forecasting the future changes.
In fact, the way it measures the ice thickness is pretty smart. Cryosat actually carries one of the highest resolution synthetic aperture radars every put into orbit. With that, it sends down microwave pulses, and then detects the reflection of the pulses from both the top and bottom surface of ice sheets, picking up information about cracks in the ice, too.
With a bit of simple maths, that means the team can work out the thickness of the ice. Prof Volker Liebig, one of the researchers behind the project, explains to the BBC:
"The message is that Cryosat is working extremely well. Its data are very reliable and the measurements we have match reality. We now have a very powerful tool to monitor the changes taking place at the poles."
The newly released data shows an entire seasonal cycle for the Arctic ice — from October 2010 to March 2011 — and pegs the total volume of sea ice in the central Arctic at 14,500 cubic kilometres in March 2011. There are years more data to come from Cryosat; let's just hope its results defy expectations. [ESA and BBC]
Images: ESA and CPOM/UCL/ESA/Planetary Visions