The Offshore and Coastal Dispersion (OCD) Model: Revisions and Evaluations
The Offshore and Coastal Dispersion (OCD) Model simulates plume dispersion and transport from offshore point, area, or line sources to receptors on land or water. The OCD model is an hour-by-hour steady state Gaussian model with enhancements that consider the differences between overwater and overland dispersion characteristics, the sea-land interface, and platform aerodynamic effects. A revised OCD model (Version 4) (or OCD/4) has been developed that includes modifications to boundary layer parameterizations and dispersion model assumptions. An overview of the physical and theoretical aspects of the model is given, along with the results of a statistical model evaluation exercise that compares the revised model (OCD/4) with the earlier OCD model (Version 3) (or OCD/3). Data from four field experiments (Ventura, Pismo Beach, and Carpinteria, California; Cameron, Louisiana) are used to evaluate the model performance. The reader is referred to the report by DiCristofaro and Hanna (1989) for detailed discussions of the points that are only briefly reviewed in this paper.
KeywordsLine Source Complex Terrain Normalize Mean Square Error Plume Height Virtual Source
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