Time Dependent Flow Of Atlantic Water On The Continental Slope Of The Beaufort Sea Based On Moorings

The flow and transformation of warm, salty Atlantic-origin water (AW) in the Arctic Ocean plays an important role in the global overturning circulation that helps regulate Earth's climate. The heat that it transports also impacts ice melt in different parts of the Arctic. This study uses data from a mooring array deployed across the shelf/slope of the Alaskan Beaufort Sea from 2002-2004 to investigate the flow of AW. A short-lived "rebound jet" of AW on the upper continental slope regularly follows wind-driven upwelling events. A total of 57 such events, lasting on average 3 days each, occurred over the 2 year period. As the easterly wind subsides, the rebound jet quickly spins up while the isopycnals continue to slump from their upwelled state. The strength of the jet is related to the cross-slope isopycnal displacement, which in turn is dependent on the magnitude of the wind, in line with previous modeling. Seaward of the rebound jet, the offshore-most mooring of the array measured the onshore branch of the AW boundary flowing eastward in the Canada Basin. However, the signature of the boundary current was only evident in the second year of the mooring timeseries. We suspect that this is due to the varying influence of the Beaufort Gyre in the two years, associated with a change in pattern of the wind stress curl that helps drive the gyre.Plain Language Summary The flow and transformation of warm, salty Atlantic-origin water (AW) in the Arctic Ocean plays an important role in the global overturning circulation that helps regulate Earth's climate. The heat that it transports also impacts ice melt in different parts of the Arctic. This study uses two years of mooring data across the continental shelf and slope of the Alaskan Beaufort Sea to investigate the time-dependent flow of AW. Short-lived bursts of AW, known as "rebound jets", occur following easterly wind storms throughout the year. Our measurements support the dynamical explanation for the events previously deduced from numerical modeling. Farther offshore, the mooring array measured one of the branches of the AW boundary current in the Canada Basin. The signature of this flow appears to vary according to the rotation of winds over the basin, which helps drive the Beaufort Gyre. Our results imply a dynamical connection between the gyre and the boundary current, motivating further study.