London: A new study has delinked an unusually large summer cyclone originating in Siberia from last year`s record low for Arctic sea ice.
The freak storm, dubbed the `Great Arctic Cyclone of August 2012`, happened to be the most powerful ever seen during the month of August, and the 13th most powerful of all Arctic storms in more than three decades of satellite records, say researchers, the journal Geophysical Research Letters reports.
"The effect is huge in the immediate aftermath of the cyclone, but after about two weeks the effect gets smaller.
"By September, most of the ice that melted would have melted with or without the cyclone," says Jinlun Zhang, oceanographer at the University of Washington`s Applied Physics Lab, who led the study, according to a Washington statement.
"The storm was enormous," said co-author Axel Schweiger, polar scientist at Washington`s Applied Physics Laboratory.
"The impact on the ice was immediately obvious, but the question was whether the ice that went away during the storm would have melted anyway because it was thin to begin with."
The research team performed the climate scientist`s equivalent of a forensic exam. They ran a computer simulation of last summer`s weather and compared it against a second scenario that was identical except that there was no cyclone.
Results showed the storm caused the sea ice to pass the previous record 10 days earlier in August than it would have otherwise, but only reduced the final September ice extent by 150,000 square km, less than a five percent difference.
By comparison, the actual minimum ice extent was 18 percent less than the previous record set in 2007.