FY 1977

The use of a diagnostic circulation model for oil trajectory analysis

Galt, J.A., and C.H. Pease

In Proceedings, 1977 Oil Spill Conference, New Orleans, LA, 8–10 March 1977, 447–454 (1977)

A diagnostic circulation model designed for the continental shelf region was used to study water parcel trajectories. The model assumes a combination of geostrophic plus Ekman dynamics and is diagnostic in that it uses fluid density data (obtained from a typical oceanographic cruise; i.e., STD stations) and wind stress data to specify the baroclinic and surface Ekman modes of the flow. The model then solves for the remaining barotropic and bottom Ekman modes subject to the constraints imposed by continuity and bathymetry. Variations in the boundary conditions correspond to variations in the mean inflow/outflow surface currents, or barotropic mode. Using this correspondence, the model was keyed to the measurements obtained from a moored current meter array and a time stepping procedure was developed. This allows the model to generate a continuous time- and space-varying representation of the regional flow field. Field data for the Northeast Gulf of Alaska were used in the model equations which were solved using finite element techniques. The predicted currents and trajectories for a variety of runs were compared against observational data.