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Abstract
A series of hydrographic surveys and monitoring instrument deployments were performed within the Georgia Coastal Ecosystem Long Term Ecology Research domain and across the adjacent region of the South Atlantic Bight (SAB). The result were also compared to the finite volume community ocean model (FVCOM) for the Georgia Coastal Ecosystem domain for the year 2014. The region contains three major sounds - Sapelo, Doboy, and Altamaha Sounds - and lies adjacent to the widest portion of the SAB. In 2014, the Winter and Spring seasons experienced high river discharge from the Altamaha River, while Summer and Fall seasonal discharges were relatively low. There was also a strong nor'easter event in early April that corresponded to high northerly winds. Bottom mounted acoustic Doppler current profilers (ADCP) within the sounds indicate that the tides are dominated by the lunar semidiurnal constituent (M2) and the shallow water overtide (M4). Removing the dominant tidal constituents from 24 hour surveys spanning the width of the navigable portion of each of the Sounds results in a net residual export of estuarine waters across all four seasons, with exports being somewhat higher and more to the south during periods of high discharge. Hydrographic surveys on the SAB also show the extent of freshwater intrusion on the shelf with maximal extent during high discharge. Empirical orthogonal function analysis of moorings placed on the SAB during April, 2014 indicate that there are two major modes driving cross shelf flows within the region: along-shore wind stress and freshwater discharge in the coastal waters. Bottom cross shelf flows dictated by wind stress and the impact of winds is larger further offshore. There is only a single major mode apparent in the along shelf flow of coastal waters. The spatial observations are in agreement with model output generated by the FVCOM for the GCE domain.