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.