The fifth lowest maximum extend in the satellite record
NSIDC has issued an update to Arctic Sea Ice News & Analysis describing winter sea ice conditions in the Arctic Ocean.
Arctic sea ice reached its maximum extent for the year on March 21 at 14.91 million square kilometers (5.76 million square miles), making it the fifth lowest maximum in the satellite record.
Arctic sea ice reached its annual maximum extent on March 21, after a brief surge in extent mid-month. Overall the 2014 Arctic maximum was the fifth lowest in the 1978 to 2014 record. Antarctic sea ice reached its annual minimum on February 23, and was the fourth highest Antarctic minimum in the satellite record. While this continues a strong pattern of greater-than-average sea ice extent in Antarctica for the past two years, Antarctic sea ice remains more variable year-to-year than the Arctic.
Average ice extent for March 2014 was the fifth lowest for the month in the satellite record. Through 2014, the linear rate of decline for March ice extent is 2.6% per decade relative to the 1981 to 2010 average.
Ice age tracking confirms large increase in multiyear ice
Satellite data on ice age reveal that multiyear ice within the Arctic basin increased from 2.25 to 3.17 million square kilometers (869,000 to 1,220,000 square miles) between the end of February in 2013 and 2014. This winter the multiyear ice makes up 43% of the icepack compared to only 30% in 2013. While this is a large increase, and may portend a more extensive September ice cover this year compared to last year, the fraction of the Arctic Ocean consisting of multiyear ice remains less than that at the beginning of the 2007 melt season (46%) when a large amount of the multiyear ice melted.
The percentage of the Arctic Ocean consisting of ice at least five years or older remains at only 7%, half of what it was in February 2007. Moreover, a large area of the multiyear ice has drifted to the southern Beaufort Sea and East Siberian Sea (north of Alaska and the Lena River delta), where warm conditions are likely to exist later in the year.
Source and Image Credit: NSIDC
For more information please read the full analysis
| Arctic sea ice minimum |
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The Arctic sea ice minimum marks the day, each year, when the sea ice extent is at its lowest. The sea ice minimum occurs at the end of the summer melting season. The summer melt season usually begins in March and ends sometime during September. The sea ice minimum has been occurring later in recent years because of a longer melting season. However, ice growth and melt are local processes; sea ice in some areas will have already started growing before the date of the sea ice minimum, and ice in other areas will still shrink even after the date of the minimum. Changes in the timing of the sea ice minimum extent are especially important because more of the sun’s energy reaches Earth’s surface during the Arctic summer than during the Arctic winter. As explained above, sea ice reflects much of the sun’s radiation back into space, whereas dark, ice-free ocean water absorbs more of the sun’s energy. So, reduced sea ice during the sunnier summer months has a big impact on the Arctic’s overall energy balance. |
| Arctic sea ice maximum |
| The Arctic sea ice maximum marks the day of the year when Arctic sea ice reaches its largest extent. The sea ice maximum occurs at the end of the winter cold season.
The Arctic cold season usually begins in September and ends in March. Monitoring winter sea ice is important to understanding the state of the sea ice. Scientists have found that Arctic sea ice has been recovering less in the winter, meaning the sea ice is already “weak” when the summer melting season arrives. A possible cause is that the underlying ocean is warmer. |
