Arctic sea ice likely reached its 2018 lowest extent on Sept. 19 and again on Sept. 23, 2018. Analysis of satellite data showed that, at 1.77 million square miles (4.59 million square kilometers), 2018 effectively tied with 2008 and 2010 for the sixth lowest summertime minimum extent in the satellite record.
Arctic sea ice, the cap of frozen seawater blanketing most of the Arctic Ocean and neighboring seas in wintertime, follows seasonal patterns of growth and decay. It thickens and spreads during the fall and winter and thins and shrinks during the spring and summer. But in the past decades, increasing temperatures have led to prominent decreases in the Arctic sea ice extents, with particularly rapid decreases in the minimum summertime extent. The shrinking of the Arctic sea ice cover can ultimately affect the planet's weather patterns and the circulation of the oceans.
One of the most unusual features of this year's melt season has been the reopening of a polynya-like hole in the icepack north of Greenland, where the oldest and thickest sea ice of the Arctic typically resides. In February of this year, a similar opening appeared in the same area, catching the attention of sea ice scientists everywhere. The first appearance of the hole raised concerns about the possibility that the region could became vulnerable if the original, thicker ice cover was replaced with thinner ice as the exposed seawater refroze. NASA's Operation IceBridge mission probed the area in March, finding that the ice was indeed thinner and thus more susceptible to be pushed around by the winds and ocean currents.
With the successful launch of NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2, on Sept. 15, scientists will be able to use the data from the spacecraft's advanced laser altimeter to create detailed maps of sea ice thickness in both the Arctic and the Antarctic.
Arctic sea ice, the cap of frozen seawater blanketing most of the Arctic Ocean and neighboring seas in wintertime, follows seasonal patterns of growth and decay. It thickens and spreads during the fall and winter and thins and shrinks during the spring and summer. But in the past decades, increasing temperatures have led to prominent decreases in the Arctic sea ice extents, with particularly rapid decreases in the minimum summertime extent. The shrinking of the Arctic sea ice cover can ultimately affect the planet's weather patterns and the circulation of the oceans.
One of the most unusual features of this year's melt season has been the reopening of a polynya-like hole in the icepack north of Greenland, where the oldest and thickest sea ice of the Arctic typically resides. In February of this year, a similar opening appeared in the same area, catching the attention of sea ice scientists everywhere. The first appearance of the hole raised concerns about the possibility that the region could became vulnerable if the original, thicker ice cover was replaced with thinner ice as the exposed seawater refroze. NASA's Operation IceBridge mission probed the area in March, finding that the ice was indeed thinner and thus more susceptible to be pushed around by the winds and ocean currents.
With the successful launch of NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2, on Sept. 15, scientists will be able to use the data from the spacecraft's advanced laser altimeter to create detailed maps of sea ice thickness in both the Arctic and the Antarctic.
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