Application of Unstructured-Grid Finite Volume Coastal Ocean Model (FVCOM) to the Gulf of Mexico hypoxie zone

Abstract

We describe the application of Unstructured-Grid Finite Volume Coastal Ocean Model (FVCOM) to the Gulf of Mexico hypoxia region. The model was forced with the observed freshwater fluxes from the Mississippi and Atchafalaya Rivers, surface winds, heat fluxes, tides, and offshore conditions. The simulations were carried from April to September 2002, and the model skill was evaluated against several independent series of observations that included tidal gauge data, ADCP data, shipboard measurements of temperature and salinity, vertical salinity and sigma-t profiles, and satellite imagery. We use trajectories of Lagrangian particles released from the Mississippi and Atchafalaya rivers to delineate the regions of strong riverine influence under different wind forcing. We also show that the frequency of cold fronts strongly influences the seasonal cycle of water column stratification.