Development of a Pre-Operational Coastal Ocean Model for Mississippi Sound and Bight

Abstract The Mississippi Sound and Bight is a complex coastal system with shallow estuarine waters that are highly vulnerable to the effects of climate change and anthropogenic influences. In order to further our understanding of the system and provide natural resource managers and decision-makers with science-based guidance, a pre-operational coastal ocean forecast system has been developed using the Coupled Ocean Atmosphere Wave Sediment Transport Modeling System (COAWST). The COAWST application for Mississippi Bight (msbCOAWST) can be run in hindcast mode, pre-operational daily mode, or forecast mode and relies on other operational models including the National Water Model (NWM) for river forcing, the High Resolution Rapid Refresh model (HRRR) for atmospheric forcing, and the Navy Coastal Ocean Model (NCOM) for open boundary forcing. msbCOAWST is being validated using data from a variety of in situ measurements that quantify coastal processes, including tides, and water quality (i.e. temperature and salinity). The highest model skill is obtained for temperature followed by water levels and salinity. msbCOAWST has been used to provide guidance for quantifying how freshwater influences derived from river diversion operations impact habitat suitability for oysters. The model is currently being extended to include waves, sediment transport, and biogeochemistry and in the future will be linked with ecological models so as to comprehensively reveal consequential environmental concerns such as harmful algal blooms and the onset and persistence of hypoxia, with their associated impacts on the region’s fisheries and shellfisheries.