Lake Effect (Cryosphere)

Lake effect in the cryosphere describes how an open-water area surrounded by sea ice, a polynya or wide lead, behaves thermally like an inland lake by exchanging large amounts of heat and moisture with the cold polar atmosphere. With the insulating ice cover gone, the exposed ocean loses heat rapidly, drives strong evaporation and convection, and produces local cloud, fog, and snowfall downwind, much as a warm lake fuels lake-effect snow. The intense ocean-to-air heat loss cools the surface water, triggers new frazil and grease-ice formation, and through brine rejection during freezing helps form dense water. Coastal polynyas are major sites of sea-ice production by this mechanism.