The polar regions are the coldest places on Earth. The Sun does not climb so high in the sky in the summer, and remains below the horizon through the long night of the winter months. Heat flows to the poles from the warmer Equator, carried by atmospheric and ocean currents. This poleward transport of heat is the primary driver of the global climate. Without it the poles would be much colder, and the tropics much warmer, than they currently are.
The North Pole is surrounded by the Arctic Ocean, an almost enclosed sea with connections to the Pacific Ocean through the Bering Strait and to the North Atlantic. The top layer of surface water in the Arctic Ocean freezes every winter. The area of ice roughly doubles in extent, making it the second largest seasonal change in the northern hemisphere (after snowfall). Even in summer, large areas of sea ice remain, its distribution controlled by atmospheric winds and ocean currents.
The thin layer of sea ice, covering about 7% of the world's ocean surface, plays an important role in the Earth's climate. Although the latest global climate models include improved representation of sea ice, they need to be verified by regular, detailed observational data. The GlobICE project aims to provide such data, generating ice motion products every three days on a spatial scale ten times finer than previously achieved, across the entire Arctic Ocean basin.