Applications of oilspill trajectory models to the Alaskan Outer Continental Shelf

Oilspill risks have been estimated for Outer Continental Shelf (OCS) regions of Alaska using a variety of ocean circulation/trajectory models and a single tracking/probability model. A number of circulation/trajectory models were required because the physical processes advecting oilspills vary throughout the Alaska coastal regions. The two most important factors influencing the movement of oil are ocean currents and local wind stress. Modeling work has been completed for the Northern Gulf of Alaska. Kodiak Island Area. Cook Inlet-Shelikof Strait, Bristol Bay (St. George Basin), Norton Sound, and Beaufort Sea (Diapir Field). The development of an efficient coordinate transformation procedure enabled the use of a common tracking/probability model for the calculation of oilspill risks. The common tracking/probability model traces hypothetical oilspill trajectories through a matrix of grid cells that contain information about the location of environmental resources (targets) which may be vulnerable to oilspills. In this way, the probability that an oilspill, starting at a given location, will contact a specific target could be calculated. Probabilities of oilspill contacts with targets were calculated for spills traveling for periods of 3, 10 and 30 days.