FY 1985

On the wind-driven variability of the flow through Bering Strait

Aagaard, K., A. Roach, and J.D. Schumacher

J. Geophys. Res., 90(C4), 7213–7221, doi: 10.1029/JC090iC04p07213 (1985)

Analysis of time series from 1981–82 near Bering Strait shows the meridional wind component, the current, and the oceanic pressure gradient to be well correlated. We argue that because of the constraining coastal geometry, there are wind-driven flow divergences which perturb the oceanic pressure field and account for the majority of the current variability. For example, northerly winds cause a pronounced set-down of sea level southeast of Bering Strait, and if the winds are strong enough, they will reverse the mean slope downward to the north through the strait. Winds during 1976–77 were also well correlated with the Bering Strait transport estimates of Coachman and Aagaard (1981), and we therefore use the calculated winds from 1946–82 to examine the low-frequency transport variability. There is a marked seasonal cycle, with summer transport about 50% greater than during winter. The long-term mean transport is calculated as less than 0.6 Sv, which is much lower than earlier estimates. Abnormally large transports apparently occurred during a number of years from 1948–67, but during the past 15 years transports have tended to be considerably less, corresponding to the stronger northerly winds during these years. The interannual wind variability near Bering Strait, together with the corresponding variability in the transport through the strait, is in fact part of the large-scale variability of the atmospheric circulation over the North Pacific and its oceanic effects.