Arctic circulation regimes

• Published in: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
• Main Authors: Proshutinsky, Andrey, Dukhovskoy, Dmitry, Timmermans, Mary-Louise, Krishfield, Richard, Bamber, Jonathan L.
• Format: Text
• Language: English
• Published: The Royal Society Publishing 2015
• Subjects: Articles; Arctic; Arctic Ocean; Greenland; Sea ice; Subarctic
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4607701/; http://www.ncbi.nlm.nih.gov/pubmed/26347536; https://doi.org/10.1098/rsta.2014.0160

Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability.