Animation of Annual Variation in Sea Ice Extent in the Northern Hemisphere
This animation shows the annual variation of sea ice extent in the Northern Hemisphere. Throughout the winter the cold temperatures freeze more and more of the water in the Arctic Ocean and surrounding bodies of water, gradually building up a layer of ice on the surface that covers millions of square kilometers. This ice pack generally reaches its maximum extent around March.
As warmer temperatures arrive in the Arctic in the springtime, the ice begins to melt and much of the ice pack breaks up. This continues throughout the summer, so the extent of the ice pack is usually at its minimum around September. Thereafter it begins growing again, repeating the annual cycle.
This animation shows seven years of this cycle, from January 2002 through December 2008.
(Note: If you cannot see the animation you may need to download the latest QuickTime player.)
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