Antarctic sea ice is a part of the ice cover of Antarctica located above the coastal Antarctic seas.
Content
Description
The area of the Antarctic ice sheet is 14 million km², the volume is 30 million km³ of ice. In the summertime (in the southern hemisphere - winter ), the area of the Antarctic ice sheet increases by 3-4 million km². This happens due to an increase (increase) in the area of ice shelves. This process is especially pronounced in the Ross Sea and on the territory of the Antarctic Peninsula . As a result of the freezing of the seas surrounding Antarctica, 17 million km² of the water surface is covered with ice [1] . In summer, these ices, as a rule, almost completely melt [2] .
As a rule, snow cover is formed in areas of annual ice. During thaws, part of the snow melts and, when it freezes, it turns into ice, and therefore the structure of the upper layer of ice changes.
Fields of annual ice, formed from ice floes that have been frozen together, can measure over 10–15 kilometers. Icefields, which arose in weak wind, differ from the fields formed in strong winds. The size of the first can reach 3-10 kilometers, they have a rounded or angular shape. Ice of considerable thickness, as a rule, is covered with ridges of hummocks and cracks.
State
At present, the area of the Antarctic sea ice in winter period reaches greater values than several decades ago. In 2014, the ice cover area around Antarctica reached a record level. On September 19, 2014, ice covered the maximum territory of the Antarctic seas since the start of observations in the 1970s. Its maximum value reached 20.14 million km², an average maximum of 5 days in a row was registered on September 22 of the same year and amounted to 20.11 million km², while in the period from 1981 to 2010 this value reached 18.72 million km² [3] .
This trend is due to a change in the wind rose . Changes began in 1992. Gusts of strong wind spread the ice over a large area and drive them away from the coast. Therefore, in recent decades, the area of Antarctic sea ice has increased. It is also worth noting that, despite the increase in sea-ice area, the area of some sections of the Antarctic ice sheet is currently decreasing.
Literature
Markov K.K., Bardin V.I., Lebedev V.L. and others. Geography of Antarctica. M., 1968
Trёshnikov A.F. Antarctic. Research, discoveries. L., 1980
Savatyugin LM, Preobrazhenskaya MA Map of Antarctica: Names and Fates / ed. Dr. Econ. Sciences, Cand. geogr. Sciences M.V. Slipenchuk. - SPb .: GeoGraf, 2014. - 352 pp., Ill. - (Polar stories) - ISBN 978-5-902211-29-7 .
A. Trёshnikov. History of discovery and exploration of Antarctica. - M .: Geografgiz, 1963. - 432 p. - (Discovery of the Earth).
Ore A.N. The phenomenon of Antarctica. - Tomsk: STT, 1999. - 128 p.
Notes
- ↑ Sea ice . www.geogr.msu.ru. The appeal date is February 6, 2016.
- ↑ Data | Data at NSIDC | National Snow and Ice Data Center . nsidc.org. The appeal date is February 6, 2016.
- ↑ The area of sea ice in the Antarctic reached a record high . RIA News. The appeal date is February 6, 2016.