Polar Front (Cryosphere)

The polar front in the cryospheric and oceanographic sense is the boundary separating cold polar water from warmer subpolar water, marked by sharp gradients in temperature, salinity, and density. In the Southern Ocean the Antarctic Polar Front, part of the Antarctic Circumpolar Current, is where cold Antarctic surface water sinks beneath warmer subantarctic water near 50 to 60 degrees south, a major biological and climatic divide. Polar fronts steer the position of the sea-ice edge, concentrate nutrients and productivity, and spawn frontal eddies and meanders. They shift seasonally and interannually, so their location helps define operational ice limits and fishing grounds.