NSIDC observes downward trend in ice extent
The National Snow & Ice Data Center (NSIDC) announced that on September 13, Arctic sea ice reached its likely minimum extent for 2013. The minimum ice extent was the sixth lowest in the satellite record, and reinforces the long-term downward trend in Arctic ice extent.
Sea ice extent will now begin its seasonal increase through autumn and winter.Meanwhile, in the Antarctic, sea ice extent reached a record high on September 18, tied withlast year’s maximum.
NSIDC notes that this is a preliminary announcement. Changing winds could still push ice floes together, reducing ice extent further. NSIDC scientists will release a full analysis of the melt season in early October, once monthly data are available for September.
Overview of conditions
On September 13, 2013, sea ice extent dropped to 5.10million square kilometers (1.97million square miles). This appears to have been the lowest extent of the year. In response to the setting sun and falling temperatures, ice extent will now climb through autumn and winter. However, a shift in wind patterns or a period of late season melt could still push the ice extent lower. The minimum extent was reached twodays earlier than the 1981 to 2010 average minimum date of September 15.
The orange line shows the 1981 to 2010 median extent for that day. The black cross indicates the geographic North Pole. Click on image to enlarge.
(Image Credit:National Snow and Ice Data Center)
Conditions in context
This years minimum was 1.69 million square kilometers (653,000 square miles) above the record minimum extent in the satellite era, which occurred on September 16, 2012, and 1.12 million square kilometers (432,000 square miles) below the 1981 to 2010 average minimum.
The graph above shows Arctic sea ice extent as of September 19, 2013, along with daily ice extent data for five previous years. 2013 is shown in blue, 2012 in green, 2011 in orange, 2010 in pink, 2009 in navy, and 2008 in purple. The 1981 to 2010 average is in dark gray. Click on image to enlarge.
(Image Credit: National Snow and Ice Data Center)
Varying distribution of ice in 2013 versus 2012
Comparing this year’s minimum extent to 2012, while extent was higher on average this year, there were variations from region to region. There was considerably higher sea ice extent in the Beaufort, Chukchi, and East Siberian sea regions, with the ice edge several hundred kilometers farther south compared to last year. This year the Canadian Archipelago also retained much more ice, keeping the Northwest Passage closed.The most notable area of less ice this year compared to last was off the east coast of Greenland, south of Fram Strait.Other small areas of decreased extent were found north of the Kara and Laptev seas.
This image compares differences in ice-covered areas between September 13, 2013, the date of this year’s minimum, and September 16, 2012, the record low minimum extent. Light gray shading indicates the region where ice occurred in both 2013 and 2012, while white and dark gray areas show ice cover unique to 2013 and to 2012, respectively.
(Image Credit:National Snow and Ice Data Center)
NASA Scientific Visualization Studio also producedan animation of this summers sea ice extent. To learn more watch: Daily Arctic Sea Ice extent from May to September 2013 Also read:Arctic sea ice continues to thin |
Source: NSIDC