Shelf-basin Exchange in the Bering Canyon in Southeastern Bering Sea: Role of Unimak Pass

Shelf-basin exchanges in the southeastern Bering Sea have significant implications for primary production on the Bering Sea shelf; yet, the mechanisms controlling such exchange are not well understood. One area with potentially enhanced cross-shelf transport is the Bering Canyon, where flow through the relatively shallow Unimak Pass meets and interacts with the Aleutian North Slope Current (ANSC). As a result, the ocean circulation and water properties in the area are influenced by local as well as remote wind forcing, ocean bathymetry, tides, and exhibit high spatial and temporal variability on multiple scales. In this study, we use ocean in situ measurement and numerical modeling to examine processes influencing shelf-basin exchange in the Bering Canyon. Results thus far suggest that on seasonal and longer time scales, the onshore flow across the Bering Canyon left rim is influenced by the Unimak pass transport, and to a lesser extent by the transport associated with the ANSC. Both Unimak Pass transport and ANSC transport are highly correlated with the along-shore wind stress south of the Aleutian Island Chain, but the Unimak Pass transport responds faster to the along-shore wind forcing by a month. These results highlight the importance of Unimak Pass in influencing the regional circulation and on-shelf transport. Numerical experimentation will be used to further elucidate the effects of tidal mixing and advection associated with Unimak Pass.