Role of Greenland Meltwater in the changing Arctic

Lead Author Dmitry, Dukhovskoy
Institution Contact Florida State University Center for Ocean-Atmospheric Prediction Studies P.O. Box 3062741 Tallahassee, FL 32306-2741 850-644-1168 (phone) 850-644-4841 (fax)
Co-Authors Andrey Proshutinsky, Woods Hole Oceanographic Institution, USA Paul Myers, University of Alberta, Canada Gennady Platov, Novosibirsk State University Jonathan Bamber, University of Bristol, UK Mary-Louise Timmermans, Yale University, USA Beth Curry, University of Washington, USA Raquel Somavilla, Spain Institute of Oceanography, Spain Yevgeny Aksenov, National Oceanography Center, UK
Theme Theme 1: Vulnerability of Arctic Environments
Session Name 1.2 Fresh Water in the Arctic Climate System: Consequences of Global Climate Change and Future Projections of the Arctic Environment
Datetime Thu, Sep 15, 2016 02:15 PM - 02:30 PM
Presentation Type Oral
Abstract text Observational data show that the Arctic Ocean environment has significantly and rapidly changed over the last few decades - change that is unprecedented in the observational record. One of the most intriguing manifestations of change is the cessation of decadal Arctic climate variability in the 21st century. Between 1948 and 1996, the Arctic atmospheric circulation alternated between anticyclonic circulation regimes and cyclonic circulation regimes with a period of 10-15 years. Since 1997, however, the Arctic system has been dominated by an anticyclonic regime. Previous studies indicate that in the 20th century, freshwater and heat exchange between the Arctic Ocean and the North Atlantic were self-regulated and their interactions were realized via quasi-decadal climate oscillations. The presented work is motivated by our hypothesis that in the 21st century, these regular oscillations have been interrupted as a result of an additional freshwater source associated with Greenland ice sheet melt. Accelerating since the early 1990s, the Greenland Ice sheet mass loss exerts a significant impact on thermohaline processes in the sub-Arctic seas. Surplus Greenland freshwater, the amount of which steadily approaching the freshwater volume fluxed into the region during the Great Salinity Anomaly events, can spread and accumulate in the sub-Arctic seas influencing convective processes there and thus interrupting quasi-decadal oscillations of the Arctic circulation regimes. The question arises where the surplus Greenland freshwater has propagated. In order to investigate the fate and pathways of Greenland freshwater in the sub-Arctic seas and to determine how and at what rate Greenland freshwater propagates into the convective regions, a numerical experiment with a coupled 1/12° HYbrid Coordinate Ocean Model (HYCOM) and Los Alamos sea ice code (CICE) has been conducted. The experiment uses a passive tracer to track propagation of Greenland freshwater within the sub-Arctic. Results from this model experiment are analyzed in the context of observed salinity changes in the sub-Arctic seas.
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