It's midwinter in the Arctic, and the sun has yet to rise over the North Pole,
But the Arctic is unusually warm for this time of year, with temperatures above freezing in the area north of Greenland.
Sea ice in this region should be thick and strong, but satellite data show the ice breaking up, exposing open sea.
Satellite data help us understand changes in the warming Arctic,
And in March, NASA's Operation IceBridge will provide detailed airborne measurements of sea ice in this region.