Aerial view of Accomplishment Creek and the Sagavanirktok River in the Brooks Range of Alaska.  Photo by D.L. Kane


Fresh Water Budget of the Arctic and High Latitude Mode of Atmospheric Variability


Bruno Tremblay (tremblay@brassens.ldgo.columbia.edu), Columbia University



The net formation of sea ice in the Arctic Ocean and its melting at lower latitudes in the Greenland, Iceland, Norwegian (GIN) and Labrador seas constitute a net transport of fresh water from the Arctic into the northern North Atlantic. The resulting salinization of the Arctic surface water and freshening of the North Atlantic surface water have an impact on the thermohaline component of the ocean current in both regions. The dominant source of fresh water for the GIN Sea has generally been associated with sea ice; however, recent measurements of the Fram Strait currents reveal that the fresh water transport by the ocean may be as large as twice that of the ice. The main goals of this study are: to quantify the contribution of the surface ocean currents to the year-to-year variability in fresh water transport from the Arctic into the Greenland and Labrador seas; to better understand the link between this fresh water transport and atmospheric forcing, especially atmospheric modes of variability such as the North Atlantic Oscillation (NAO); and to better understand the role of buoyancy fluxes and mechanical forcing in driving spatial changes to the mixed layer depth which are linked to fresh water export. This study builds on previous work done by the authors on the variation of sea ice transport through Fram Strait and its relation with atmospheric modes of variability; and on the distribution of meteoric waters in the Arctic surface waters. In this proposal we expand our view to the fresh water budget over the Arctic Ocean, including: sea ice melt and freezing; mixed-layer depth; fresh water flux from river runoff, Bering Strait inflow and Canadian Arctic Archipelago (CAA) outflow; and precipitation and evaporation. To this end, a 3-dimensional coupled sea-ice ocean model of the Arctic and North Atlantic oceans will be integrated for 53-years using NCEP reanalysis atmospheric forcing. A simpler coupled model using a two-layer ocean will also be run using idealized forcing and geometry to study individual dynamic modes of the ocean-ice system to help in the interpretation of the 3-D simulations.




Arctic CHAMP
Science Management Office

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Photo: Aerial view of Accomplishment Creek and the
     Sagavanirktok River in the Brooks Range of Alaska.  Photo by D.L. Kane