Image Credit: National Snow and Ice Data Center IUP Bremen
From Live Science:
Months before Hurricane Sandy hurled the Atlantic Ocean into houses and cities along the East Coast, another record-breaking cyclone battered North America, helping push this year’s Arctic sea ice to a record low, a new study finds.
Arctic sea ice has been declining for decades, reaching a record low in September 2007 and hitting that record again in 2012.
“The Great Arctic Cyclone of August 2012″ arose in Siberia on Aug. 2 and crossed the Arctic Ocean to Canada, lasting an unusually long 13 days. The cyclone hit a pressure minimum of 966 millibars on Aug. 6, the lowest ever recorded for an Arctic storm, professors Ian Simmonds and Irina Rudeva of the University of Melbourne in Australia report in the Dec. 15 issue of the journal Geophysical Research Letters. The pressure reading is only 26 mb higher than Hurricane Sandy’s record low of 940 mb. (A typical low-pressure system usually hits around 1,000 mb.)
“This pressure minimum and cyclone longevity are very atypical of Arctic storms, particularly in August,” the authors write in the study. “We conclude that [the storm] was the most extreme August Arctic cyclone.”
In terms of key properties, including pressure and radius, the Arctic cyclone ranks 13 out of all 19,625 Arctic storms on record since 1979, Simmonds and Rudeva report. “This storm truly deserves the title of ‘The Great Arctic Cyclone of August 2012′,” they said.
Impact on sea ice
Simmonds and Rudeva report that the storm greatly affected the record low sea ice in the Arctic this September.
“[A]nalyses we have conducted indicate [the storm] caused the dispersion and separation of a significant amount of ice, while its removal left the main pack more exposed to wind and waves associated with [the storm], facilitating the further decay of the main pack,” they write in their report. Read More
Here’s the paper, the abstract follows:
– Analysis and diagnosis is performed on the dramatic Arctic storm of August 2012
– Storm’s evolution and longevity tied to baroclinicity and a tropopause vortex
– Storm is the most intense Arctic August system in the record (since 1979)
On 2 August 2012 a dramatic storm formed over Siberia, moved into the Arctic, and died in the Canadian Arctic Archipelago on 14 August. During its lifetime its central pressure dropped to 966 hPa, leading it to be dubbed ‘The Great Arctic Cyclone of August 2012’. This cyclone occurred during a period when the sea ice extent was on the way to reaching a new satellite-era low, and its intense behavior was related to baroclinicity and a tropopause polar vortex. The pressure of the storm was the lowest of all Arctic August storms over our record starting in 1979, and the system was also the most extreme when a combination of key cyclone properties was considered. Even though, climatologically, summer is a ‘quiet’ time in the Arctic, when compared with all Arctic storms across the period it came in as the 13th most extreme storm, warranting the attribution of ‘Great’.