Barrow Canyon volume, heat, and freshwater fluxes revealed by long‐term mooring observations between 2000 and 2008

Abstract

Barrow Canyon, in the northeast Chukchi Sea, is a major conduit for Pacific Water to enter the interior Arctic basins. Assemblies of annual (September 2000 to August 2008) temperature, salinity, and velocity data acquired from a mooring array in the mouth of Barrow Canyon and high‐resolution hydrographic and velocity transects along the mooring array in 2002, 2010, and 2011 have enabled a direct computation of volume, heat, and freshwater fluxes. Annual mean volume transport through Barrow Canyon was 0.45 Sv, which consisted of 0.44 Sv of Pacific Water and 0.01 Sv of Atlantic Water. Annual mean Pacific Water transport through Barrow Canyon represents 55% of the long‐term mean Pacific Water inflow through the Bering Strait. During summer, more of the Pacific inflow was advected to an eastern path as the Alaskan Coastal Current that flows along the Alaskan coast to Barrow Canyon. The freshwater flux through Barrow Canyon was 904 km3/yr, which is equivalent to 5% of the freshwater content of the Canada Basin. The annual averaged heat flux displayed substantial interannual variability, ranging from 0.93 to 3.02 TW, which could melt 88,000–290,000 km2 of 1 m thick ice. A relationship exists between the measured Barrow Canyon transport and local winds such that under southerly winds the northward flow of water through the canyon increases. Such wind conditions are induced by the weaker sea level pressure contrast between the Arctic and North Pacific, caused by a decrease in the pressure over the Arctic and an increase over the North Pacific.