Antarctic sea ice

Earth image on September 21, 2005, with the full Antarctic region visible

Antarctic sea ice is the sea ice of the Southern Ocean. It extends from the far north in the winter and retreats to almost the coastline every summer.[1] Sea ice is frozen seawater that is usually less than a few meters thick. This is the opposite of ice shelves, which are formed by glaciers; they float in the sea, and are up to a kilometre thick. There are two subdivisions of sea ice: fast ice, which are attached to land; and ice floes, which are not.

Sea ice that comes from the Southern Ocean melts from the bottom instead of the surface like Arctic ice because it is covered in snow on top. As a result, melt ponds are rarely observed. On average, Antarctic sea ice is younger, thinner, warmer, saltier, and more mobile than Arctic sea ice.[2] Another difference between the two ice packs, is that while there is clear Arctic sea ice decline, the trend in Antarctica is roughly flat.[1] Antarctic sea ice is not studied very well in comparison to Arctic ice since it is less accessible.

  1. ^ a b Cite error: The named reference :2 was invoked but never defined (see the help page).
  2. ^ Vaughan, D. G.; Comiso, J. C.; Allison, I.; Carrasco, J.; et al. (2013). "Chapter 4: Observations: Cryosphere" (PDF). IPCC AR5 WG1 2013. pp. 317–382.