Tuning of the OSCURS (Ocean Surface Current Simulations) Numerical Model to Ocean Surface Current Measurements in the Gulf of Alaska

摘要

An empirical model for numerical ocean surface current simulations (OSCURS) that was developed in 1988 to analyze variability in Lagrangian drift in the North Pacific Ocean and Bering Sea (north of lat. 35 degs N) was assessed. The model, which computes currents from the vector sum of geostrophic current plus wind drift, was tuned with data from the Gulf of Alaska, collected in 1978 with satellite tracked drifters drogued at 20 m. By applying incremented linear tuning coefficients to find the best fit, its sensitivity to several functions was evaluated for computing drift speed and angle of deflection of the current to the right of the wind. Despite limitations due to the computation of winds from Fleet Numerical Oceanography Center gridded sea level pressure data, the 90 km grid size, and the once daily time step, remarkably good visual agreement was obtained between the model's progressive vector tracks and two out of the three drifters available.