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Arctic sea ice still below average Winter temperatures in the Arctic have been relatively warm as the sea-ice extent continues to be relatively low for the time of year Alan Bailey Petroleum News
To someone facing the icy winds and heavy snow of the severe winter that has struck large areas of North America, the concept of the Arctic being warmer than usual may seem less than credible. But in January, Arctic temperatures were above average, according to data presented by the National Snow and Ice Data Center, or NSIDC. And, with those higher than normal temperatures, the extent of the Arctic sea-ice cover has tracked well below its long-term average, as the ice extent continues to grow towards its winter maximum.
The average ice extent in January was 5.3 million square miles, an extent 309,000 square miles below the January average between 1981 and 2010, and 61,800 square miles above the record low January extent set in 2011, NSIDC says.
Regional variation The ice extent is below average in the Barents Sea, the Sea of Okhotsk and the Bering Sea, while being close to average in Baffin Bay, the Labrador Sea and the Gulf of St. Lawrence. The below average ice conditions in the Bering Sea marks a change from recent winters, in which Bering Sea ice has been relatively extensive. The last time that below average conditions were observed in the Bering in January was in 2005, NSIDC says.
In the past three years a new satellite system has enabled measurements of estimated Arctic sea ice thicknesses, thus enabling estimates of the total ice volume, a parameter that more meaningfully represents the total amount of ice on Arctic seas than does the areal extent of the ice. These volume estimates indicate that the ice volume in the fall of 2013 was about 50 percent higher than in the fall of 2012, thanks mainly to the retention of thick, multi-year ice around northern Greenland and the Canadian Archipelago, NSIDC says. However, this apparent recovery in ice volume must be viewed in the context of long-term trends, with the October 2013 volume thought to be among the lowest volumes of the last 30 years, NSIDC says.
Arctic oscillation January air temperatures were 4 to 7 F above average over the central Arctic Ocean and 13 to 14 F above average over the North Atlantic region, NSIDC says. NSIDC attributes these temperature anomalies to a negative “Arctic oscillation” pattern, a situation in which air pressure over the Arctic is higher than normal. By contrast, December saw a positive Arctic oscillation, with lower than normal Arctic air pressures, warm conditions over Siberia and Eurasia, and cold weather in Greenland, Alaska and Canada.
According to information on the National Oceanic and Atmospheric Administration website the Arctic oscillation is linked to the polar vortex, the atmospheric feature much in the news of late as the prime culprit behind the North American freeze up. When there is a strong negative Arctic oscillation, as of late, the polar vortex, the high-altitude jet stream wind system that circles the pole, tends to weaken and meander around, allowing cold polar air to flow south.
Curiously, the polar vortex does not appear to have weakened around the entire northern hemisphere — as a consequence Alaska, Scandinavia, Europe and western Russia have seen warmer than average weather, NOAA says.
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