Using this graphic and referring to it is encouraged, and please use it in presentations, web pages, newspapers, blogs and reports.
For any form of publication, please include the link to this page and give the cartographer/designer credit (in this case Hugo Ahlenius, UNEP/GRID-Arendal)
Stroeve, J. and Meier, W. (1999 updated 2005). Sea Ice Trends and Climatologies from SMMR and SSM/I. Boulder, Colorado USA. National Snow and Ice Data Center. Digital media. http://nsidc.org/data/ smmr_ssmi_ancillary/monthly_means.html [Accessed 24 April 2007]
Armstrong, R.L. and Brodzik, M.J. (2005). Northern Hemisphere EASE-Grid weekly snow cover and sea-ice extent version 3. Boulder, Colorado USA. National Snow and Ice Data Center. Digital media. http:// nsidc.org/data/nsidc-0046.html [Accessed 24 April 2007]
Uploaded on Monday 27 Feb 2012
Maps of average sea ice extent in the Arctic summer (September) and winter (March), and in the Antarctic summer (February) and winter (September)
Hugo Ahlenius, UNEP/GRID-Arendal
Passive microwave sensors on satellites have monitored the extent of the sea ice cover since 19782. This technique is widely used to investigate fluctuations in ice extent over the seasons, variability between years, and longterm trends. The seasonal variation of ice extent is much greater in the Antarctic where there is about six times as much ice in winter as in summer. Currently, in the Arctic, ice approximately doubles from summer to winter. This figure presents sea ice extent from 1979 to 2002/2003, based on passive microwave satellite observations. The two polar regions are drawn to the same scale.