National Oceanic and
Atmospheric Administration
United States Department of Commerce


 

FY 2020

Vertical structure and temporal variability of currents over the Chukchi Sea continental slope

Stabeno, P.J., and R.M. McCabe

Deep-Sea Res. II, 177, 104805, doi: 10.1016/j.dsr2.2020.104805, View online (2020)


Observations from a single mooring site on the northern Chukchi Sea continental slope near the 1000-m isobath are presented. This site was occupied consecutively for three years (spanning September 2014–August 2017). Vertically the flow divides into three depth ranges: the upper ~200 m, ~200–~850 m and near-bottom flow. In the upper ~200 m, the mean flow was northwestward and strongest in the summer months. During winter months, currents decreased in magnitude, and in some years even reversed in direction. Satellite-tracked drifter trajectories (drogue depth ~30 m) show this along-slope flow persists at least from 156 to 165 °W, with an average velocity of ~17 cm s−1. This northwestward flowing current is the Chukchi Slope Current. From ~250 m to ~850 m, the flow reversed; this weak flow is the Arctic-wide cyclonic boundary current advecting Atlantic Water. The mean flow at ~900 m is weak and on an annual time scale not significantly different from 0 cm s−1. It consists of Arctic deep water. In the upper two layers, currents vary on the scale of days to seasons, with short-term reversals common. Currents below 40 m were not significantly correlated with local winds nor wind stress curl. We hypothesize that the northwestward flowing Chukchi Slope Current is a consequence of dynamics associated with the Beaufort Gyre.



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