Interannual changes in the Bering Strait fluxes of volume, heat and freshwater between 1991 and 2004

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Abstract

[1] Year-round moorings (1990 to 2004) illustrate interannual variability of Bering Strait volume, freshwater and heat fluxes, which affect Arctic systems including sea-ice. Fluxes are lowest in 2001 and increase to 2004. Whilst 2004 freshwater and volume fluxes match previous maxima (1998), the 2004 heat flux is the highest recorded, partly due to ∼0.5°C warmer temperatures since 2002. The Alaskan Coastal Current, contributing about 1/3rd of the heat and equation image of the freshwater fluxes, also shows strong warming and freshening between 2002 and 2004. The increased Bering Strait heat input between 2001 and 2004 (>2×1020 J) could melt 640,000 km2 of 1 m thick ice; the 3-year freshwater increase (∼800 km3) is about equation image of annual Arctic river run-off. Weaker southward winds likely explain the increased volume flux (∼0.7 to ∼1 Sv), causing ∼80% of the freshwater and ∼50% of the heat flux increases.

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