Lagrangian-Eulerian mapping in CSOMIO coupled ocean-oil-sediment-biology model

Rémi Laxenaire, Laboratoire de Météorologie Dynamique Palaiseau, Palaiseau Cedex, France, Dmitry S Dukhovskoy, Florida State University, Tallahassee, FL, United States, Steven L Morey, Florida Agricultural and Mechanical University, Distinguished Research Scientists, NOAA Center for Coastal and Marine Ecosystems, and Professor, Tallahassee, United States, Eric Chassignet, Center for Ocean-Atmospheric Prediction Studies, Florida State University, Tallahassee, United States and Xu Chen, Florida State University, Center for Ocean-Atmospheric Prediction Studies, Tallahassee, United States
Abstract:
The Deepwater Horizon oil spill launched unprecedented efforts to investigate the fate and pathways of oil in the Northern Gulf of Mexico in 2010. Yet the fate of the subsurface oil still remains unknown. This presentation describes development of a coupled ocean-oil model – the central part of the ocean-oil-sediment-biology modeling system being developed within the Consortium for Simulation of Oil-Microbial Interaction in the Ocean (CSOMIO) project funded by the Gulf of Mexico Research Initiative. A key objective of the CSOMIO project is to develop and evaluate the modeling framework for simulating oil in the marine environment, including its interaction with ecosystems and sediments. The modeling system for CSOMIO is based on the Coupled Ocean-Atmosphere-Wave-Sediment Transport model (COAWST). Central to CSOMIO’s coupled modeling system is an oil plume model coupled to the hydrodynamic model (ROMS). The oil plume model is based on Lagrangian approach that describes the oil plume dynamics by advecting and diffusing individual “floats” representing a cluster of oil droplets. The chemical composition of oil is described in terms of three components (saturates, aromatics, and heavy oil including resins and asphaltines). Oil droplets are characterized by size and chemical structure (mass fraction of compounds). The oil plume model simulates rise velocity of oil droplets based on ambient ocean flow and density fields and density and size of the oil droplets. The oil model also includes weathering processes and surface wind drift. A key component of the CSOMIO model is Lagrangian-Eulerian and Eulerian-Lagrangian mapping of the oil characteristics. This mapping is necessary for the interaction between the ocean-oil module with the sediment and biology models. The presentation discusses these algorithms and demonstrates results of the model experiments with the new modeling system.
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