FY 1987

Northward flow in the Bering and Chukchi seas

Overland, J.E., and A.T. Roach

J. Geophys. Res., 92(C7), doi: 10.1029/JC092iC07p07097, 7097–7105 (1987)

The ocean circulation on the Bering and Chukchi sea shelves is investigated using a barotropic numerical model. In the presence of the winter seasonal wind stress from the northeast, observed northward transport through Bering Strait of 0.6 Sv for the 8-month winter season 1981–1982 can be driven by a sea level difference of 0.4 m between the Pacific and Arctic oceans. This sea level difference between basins is in agreement with hydrographic estimates. In the absence of wind stress a 0.4-m sea level difference drives a northward transport through Bering Strait of 1.1 Sv. Maximum transport through Bering Strait is geostrophically limited, not frictionally or inertially limited. Major qualitative circulation features of the region are evident in the simulations. Westward intensification of the northward transport across the Bering Sea shelf is confirmed, with the major transport occurring in the relatively deep Gulf of Anadyr. In the absence of wind, Anadyr Strait contributes 72% of the northward transport through Bering Strait. With northeasterly winds there is a net clockwise circulation around Saint Lawrence Island. Within the 20-m isobath, North and Kotzebue sounds are little influenced by the general circulation. Northward transport in the Chukchi Sea bifurcates in the vicinity of Point Hope. The predominant branch is directed toward the northwest in a broad canyon feature south of Heralds Shoal, and the balance becomes the Alaskan Coastal Current between Cape Lisburne and Point Barrow.