Publication Abstract

Simulating the Dynamics and Water Properties of Mississippi Sound and Bight Using the CONCORDE Synthesis Model

Pan, C., Dinniman, M., Fitzpatrick, P. J., Lau, Y. H., Cambazoglu, M., Parra, S., Hoffman, E., Dzwonkowski, B., Warner, S., & Wiggert, J. (2018). Simulating the Dynamics and Water Properties of Mississippi Sound and Bight Using the CONCORDE Synthesis Model. 2018 Gulf of Mexico Oil Spill and Ecosystem Conference. New Orleans, LA.


Mississippi (MS) Sound and Bight and Mobile Bay area constitute a river-dominated coastal system, in which the coastal circulation, multi-point-source river input, coastal sea breeze, tidal activities, and open ocean momentum all contribute to the complexity of local water properties. As part of the modeling effort of the Gulf of Mexico Research Initiative (GOMRI)-funded CONCORDE consortium, a high resolution (~400 m) ocean model is implemented for the MS Sound and Bight. The model is based on the Coupled Ocean Atmosphere Wave Sediment Transport Modeling System (COAWST), with initial and lateral boundary conditions drawn from 1km-resolution Gulf of Mexico Navy Coastal Ocean Model (GOM-NCOM). The model initiates on 01/01/2014 and runs for more than 3 years. A low-resolution surface forcing, drawn from the North America Regional Reanalysis (NARR), and a high-resolution forcing, called the CONCORDE Meteorological Analysis (CMA) that resolves the diurnal sea breeze and other mesoscale features, are used to drive the model to examine the sensitivity of the circulation to atmospheric forcing. The model responses to the NARR forcing and to the CMA forcing are compared in detail for the CONCORDE fall and spring field campaigns when contemporaneous in situ data are available. Taylor diagrams that target the RMS errors, correlation coefficients and standard deviations between the model and observations suggest that the model has higher simulation skill when it is driven by CMA. Drifters and dye experiments near Mobile Bay demonstrate that material exchanges between Mobile Bay and the Sound, and between the Sound and Bight, are sensitive to the wind strength and direction. A model - data comparison targeting the Mobile Bay plume suggests that under both northerly and southerly wind conditions the model is capable of accurately simulating the variation of the plume in terms of velocity, plume extent, heat and salt budgets. The presentation will focus on critically assessing the contrasts in estuary-shelf exchange dynamics that are realized between the NARR and high-resolution CMA forcing.