Hybrid computer simulation of wind-driven ocean currents

This paper describes the application of a hybrid computer in the simulation of wind-driven ocean currents. The simulation is based on the mathematical model developed by Ekman. Pure digital simulation is not economical due to excessive computer time required for the solution of the partial differential equations in the model. In the hybrid computer simulation, the ability of the analog computer to solve differential equations fast and the data handling capability and programming simplicity of the digital computer are taken advantage of. The results of the computer simulation for the simplified case of a step-function change in wind show good agreement with the results obtained by other investigators. Actual time-series wind data measured from a fixed buoy were used to calculate the wind stress, which was used as input to the model. The currents computed during the simulation were then compared to currents measured concurrently with the wind data. The current meter records contained tidal components superimposed on the wind-driven currents; so statistical time-series analysis techniques were applied in correlating the data and the computer results.