COASTAL-OCEAN PROCESSES AND THEIR INFLUENCE ON THE OIL SPILLED OFF SAN-FRANCISCO BY THE M V PUERTO-RICAN/

The oil tanker M/V Puerto Rican exploded on 31 October 1984 and later broke apart to produce a major oil spill in the coastal waters off San Francisco, California, USA. Oil from this spill initially moved to th e SSW until 5 November, when it abruptly reversed direction and began moving rapidly to the north and then to the NNW during the following w eek. The oceanic processes that most likely contributed to the displac ement of the oil spilled by the Puerto Rican are examined within the f ramework of a simple, empirical-hindcasting model. A large-scale flow component, wind drift, and tidal currents are included in the model. W ind drift, inferred by using a simple linear formulation, was the sing le most important factor in determining the over-all displacement of t he oil. Residuals from the model, however, indicate that the winds alo ne could not fully account for the sudden and dramatic reversal in oil movement that occurred on 5 November 1984. This reversal was surge-li ke and coincided with an increase in sea level along the central Calif ornia coast. Finally, the close agreement between the local and advect ive changes in sea-surface temperature in the Gulf of the Farallones a t the time of the Puerto Rican oil spill indicate, although not conclu sively, that this reversal could have been related to the onset of the Davidson Current or other larger-scale flow phenomena.