Shelf-Break Exchange in the Bering, Chukchi and Beaufort Seas

Abstract

The Bering and Chukchi/Beaufort shelf-breaks form the beginning and end of the dramatic sea-level and wind-forced fl ow of Pacifi c Ocean water across the Bering and Chukchi continental shelves between the Pacifi c and Arctic Oceans. Recent model results suggest that the on-shelf fl ow in the Bering is distributed along the shelf-break, wind-dependant, focused by Zhemchug and Bering canyons and modifi ed by shelf-break eddies. Similarly, the off-shelf fl ow in the Chukchi/Beaufort is mediated by canyons, shelf-break jets, eddies, and wind forcing. In the Chukchi, fl ow is channeled through Barrow and Herald canyons to the shelf-break, where across-slope fl ow in Ekman boundary layers and instabilities result in the exchange of water and properties across the slope. In addition, dense shelf-water, created from brine rejection during ice formation in coastal polynyas, has been observed to fl ow downslope through Barrow Canyon. Along the Beaufort shelf, the shelf-break current is unstable, shedding eddies that populate the deep Beaufort basin. Upwelling favorable winds in summer have been observed to modify the structure of the shelfbreak current and drive exchange across the Chukchi and Beaufort slopes. Most of

The Arctic Ocean's Beaufort Gyre

“…In this polynya, sea-ice production can be in the range 9-15 m y −1 (compared with typical ice growth in Arctic shelf regions of approximately 1.5 m y −1 ), giving rise to an increase in the salinity of the winter waters of up to 2 g kg −1 (Winsor & Chapman 2002). A detailed overview of dense water formed in this region of the Chukchi Sea is given by Williams et al (2014).…”

Physical forcings and intense shelf–slope fluxes of particulate matter in the halocline waters of the Canadian Beaufort Sea during winter

“…Williams et al (2014) recently reviewed the control of ocean circulation by shelf-break exchange processes in the Chukchi and Beaufort seas. The shelf-basin connection is best exemplified by Pacific water that enters the Arctic Ocean through the Bering Strait, subsequently steered by topography through the Chukchi Sea, and on reaching the shelf-break is believed to turn east causing a shelfbreak current along the slope.…”

Variational Ensemble-Transform Filtering of HFR & ADCP velocities in the ice-free Chukchi Sea

“…Okko-nen et al (2009) found that flow into Barrow Canyon is strongly modulated by wind and buoyancy effects of the source ACC flow. Williams et al (2014) investigate water-mass exchanges over the shelf-breaks along the boundaries of the CS, while more recent work by Corlett and Pickart (2017) studies the current structure along the shelfbreak. Many of these studies have been aided by moored acoustic Doppler current profilers (ADCP, or moorings) and coastally-installed high-frequency radar (HFR) to monitor circulation over the region.…”