The Northern Gulf of Mexico Littoral Initiative (NGLI) was established to create a state-of-the-art ocean observing and forecasting system for the marine environment of the Mississippi Bight and adjoining sounds and bays. The modeling system, consisting of three-dimensional circulation models, a cohesive and non-cohesive sediment transport model, an atmospheric model, and a wave model, will provide a reliable means to forecast littoral circulation, sediment suspension and transport, surface waves and conservative and non-conservative water quality constituents. Currents, temperature, salinity, turbidity, and remotely sensed data are being collected for model validation via an extensive real-time/near real-time data collection network. The goal of NGLI is to become a sustained cooperative multi-agency effort that will use model forecasts and observational data for military training and coastal resource management.

The primary NGLI model, the Mississippi Bight model (ECOM - Estuarine and Coastal Oceanographic Model), produces time series of three-dimensional temperature, salinity, and currents and two-dimensional surface elevation. The modeling framework adopts a 500m resolution orthogonal curvilinear grid, which resolves the bathymetric and coastline features of the region, especially around barrier islands. ECOM represents the highest spatial resolution component of a triply nested series of three dimensional circulation models ranging from the North Atlantic Ocean to the Gulf of Mexico to the MS Bight/Sound. At its eastern and southern boundaries, ECOM is coupled to the regional Gulf of Mexico model (PDOM - Princeton/Dynalysis Ocean Model) so that energy transfer between the two models is consistent.

The circulation of the entire Gulf of Mexico basin is calculated using a version of the PDOM model that includes data assimilation. The model has a resolution of 5-6 km in the Northeastern Gulf and of 2-3 km in the Northwestern Gulf with 37 levels in the vertical including provision for both surface and bottom boundary layers. The PDOM model is nested within a North Atlantic application of the Navy Coastal Ocean Model (NCOM) in order to obtain dynamic boundary conditions. The Coupled Ocean/Atmospheric Prediction System (COAMPS) provides the meteorological forcing and satellite-derived sea surface height and sea surface temperature data are assimilated through the Navy's Modular Ocean Data Assimilation System (MODAS) to provide accurate Loop Current and Loop Current eddy morphology.

COAMPS is currently running operationally in a nested configuration, with the outer grid using a 27-km grid spacing and the inner grid a 9-km spacing. COAMPS parameters, forecasted out to 48 hrs, are used as meteorological forcing by the oceanographic models. These COAMPS parameters include precipitation, atmospheric pressure, air temperature, relative humidity, vapor pressure, latent heat flux, sensible heat flux, solar radiation, infrared flux, wind velocity, and wind stress.

COAMPS wind fields and regional WAM (WAve Model) directional wave spectra are used to drive NGLI’s coastal wave model, SWAN (Simulating WAves Nearshore), which is a third-generation model that computes random, short-crested, wind-generated waves in coastal regions and inland waters.