The Most Detailed Images of Polar Ice Cap Thickness Yet

Illustration for article titled The Most Detailed Images of Polar Ice Cap Thickness Yet

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 math, 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 by ESA and CPOM/UCL/ESA/Planetary Visions




That hole in the data is there because satellites do not go over the Earth's poles. They come close — usually about 83 degrees north and south, but this one looks like it's getting as far as 86 — but they cannot go directly over the pole while maintaining a stable orbit.

We have no satellite monitoring of the last 2-3 degrees at the North and South pole. We might have some weather sats that get low-rez pictures of the poles from geosynchronous orbit, but the low orbit Earth-monitoring satellites are blind up there.