CryoSat measures the height of the sea ice above the water line, known as the “freeboard”, to calculate the thickness. The measurements used to generate this first map of the Arctic were from January and February 2011, as the ice approaches its annual maximum. The data are exceptionally detailed and considerably better than the mission’s specification. They even show lineations in the central Arctic that reflect the ice’s response to wind stress.
A new map of Antarctica has also been created showing the height of the ice sheet. In addition, detail of edges of the ice sheet where it meets the ocean can now be closely monitored thanks to CryoSat’s sophisticated radar techniques. This is important because this is where changes are occuring.
Further information can be found at ESA