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NASA: 2015 Arctic Sea Ice Maximum Is Lowest Recorded

30.03.2015
30.03.2015 07:53 Age: 2 yrs

Click to enlarge. From the NSIDC analysis. Figure 1. Arctic sea ice extent for February 25, 2015 was 14.54 million square kilometers (5.61 million square miles). The orange line shows the 1981 to 2010 median extent for that day. The black cross indicates the geographic North Pole. Courtesy: NSIDC.

Click to enlarge. From the NSIDC analysis. Figure 2. The graph above shows Arctic sea ice extent as of March 18, 2015, along with daily ice extent data for four previous years. 2014 to 2015 is shown in blue, 2013 to 2014 in green, 2012 to 2013 in orange, 2011 to 2012 in brown, and 2010 to 2011 in purple. The 1981 to 2010 average is in dark gray. The gray area around the average line shows the two standard deviation range of the data. Courtesy: NSIDC.

 

Less than 1 per cent

Seasonal ice


Here is the analysis released by the US National Snow and Ice data Center (NSIDC) on 19 March 2015.

Arctic sea ice reaches lowest maximum extent on record

March 19, 2015

Overview of conditions

Conditions in context

Over the 2014 to 2015 winter season, sea ice extent grew 9.91 million square kilometers (3.83 million square miles). This was substantially less ice growth than last year, which saw record growth over the winter. Part of the explanation for the record low maximum lies with recent weather patterns. As discussed in our previous post, February was characterized by an unusual configuration of the jet stream, leading to warm conditions over the Pacific side of the Arctic that maintained low sea ice extent in the Bering Sea and the Sea of Okhotsk. Furthermore, since the last half of February through the middle of March, the Arctic Oscillation was in a strongly positive phase, with index values exceeding 5.0 for several days in the first week of March. This has been expressed as a strong Icelandic Low, a semi-permanent area of low atmospheric pressure found between Iceland and southern Greenland and extending into the Barents Sea. The strong Icelandic Low led to a pattern of surface winds over the Barents and Kara seas with an unusually strong component from the south.

Over the first two weeks of March, temperatures throughout the eastern Arctic at the 925 hPa level (approximately 3,000 feet altitude) were several degrees Celsius above average, with temperatures as much as 8 to 10 degrees Celsius (14 to 18 degrees Fahrenheit) above average in the Barents Sea between Svalbard and Franz Josef Land.

While the seven-day weather forecasts show continued warmer-than-average conditions over the eastern Arctic, colder-than-average conditions are expected over the Bering Sea and may still lead to some new ice formation. Thus, while the maximum appears to have occurred on February 25, late season ice growth may still occur.

Final analysis pending

At the beginning of April, NSIDC scientists will release a full analysis of winter conditions, along with monthly data for March. For more information about the maximum extent and what it means, see the NSIDC Icelights post, the Arctic sea ice maximum.

End of NSIDC analysis.

Sources

NASA here and NSIDC here.