Cryosat mission's new views of polar ice

Addis Ababa, April 25, 2012 (WIC) - Europe's Cryosat mission is now watching the ebb and flow of Arctic sea ice with high precision.

The radar spacecraft was launched in 2010 to monitor changes in the thickness and shape of polar ice..

Scientists have spent the past two years getting to grips with its data.

And on Tuesday, they reported that Cryosat was now delivering an unprecedented view of the seasonal growth and retreat of sea ice spanning the entire Arctic basin.

The researchers also released a map showing the difference in height across the Greenland ice sheet.
Click the two tabs above to see visualisations of the satellite's data.

"The message is that Cryosat is working extremely well. Its data are very reliable and the measurements we have match reality," said Prof Volker Liebig, the director of Earth Observation at the European Space Agency (Esa).

"We now have a very powerful tool to monitor the changes taking place at the poles," he told BBC News.

The Esa director delivered an update on the mission at London's Royal Society. The information was also being released here at theEuropean Geosciences Union (EGU)meeting in Vienna, Austria.

Several satellites have already detailed therecent and rapid erosion of summer sea ice extent as the Arctic has warmed.
But Cryosat's innovation has been to provide a means to get at a figure for ice volume - a far more significant number in terms of understanding the long-term viability of the ice.

To do this, the satellite carries one of the highest resolution synthetic aperture radars ever put in orbit.

According to BBC, the instrument sends down pulses of microwave energy which bounce off both the top of the ice and the water in the cracks, or leads, which separate the floes.

By measuring the difference in height between these two surfaces, scientists can, using a relatively simple calculation, work out the overall volume of the marine cover.