FY 1996

An eddy-resolving model of circulation on the western Gulf of Alaska Shelf: 1. Model development and sensitivity analyses

Hermann, A.J., and P.J. Stabeno

J. Geophys. Res., 101(C1), doi: 10.1029/95JC02681, 1129–1149 (1996)

An eddy-resolving primitive equation model was used to simulate circulation on the shelf in the western Gulf of Alaska. This paper describes the development and sensitivity analysis of the model, while a companion paper [Stabeno and Hermann, this issue] demonstrates correspondence with measured currents in specific years. The model is initialized with a salinity field derived from local conductivity-temperature-depth surveys and forced with an idealized alongshore wind stress pattern. Buoyancy forcing is achieved by freshening the salinity field along a portion of the coastal wall. The model exhibits many of the patterns evident in observations, including mean flows and mesoscale eddies associated with the Alaska Coastal Current (ACC). Sensitivity studies suggest a strong dependence of the barotropic flux of the ACC on local winds and weak dependence on upstream buoyancy forcing. Both wind and buoyancy forcing significantly affect the generation of eddies. Strong northeasterly winds enhance cross-shelf flow of the ACC to the west of Shelikof Strait, where isobaths veer southward. Strong buoyancy forcing also favors cross-shelf flow in that region and enhances the formation of eddies.