Barotropic Tides in the South Atlantic Bight

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The characteristics of the principal barotropic diurnal and semidiurnal tides are examined for the South Atlantic Bight (SAB) of the eastern United States coast. We combine recent observations from pressure gauges and ADCPs on fixed platforms and additional short-term deployments off the Georgia and South Carolina coasts together with National Ocean Service coastal tidal elevation harmonics. These data have shed light on the regional tidal propagation, particularly off the Georgia/South Carolina coast, which is perforated by a dense estuary/tidal inlet complex (ETIC). We have computed tidal solutions for the western North Atlantic Ocean on two model domains. One includes a first-order representation of the ETIC in the SAB, and the other does not include the ETIC. We find that the ETIC is highly dissipative and affects the regional energy balance of the semidiurnal tides. Nearshore, inner, and midshelf model skill at semidiurnal frequencies is sensitive to the inclusion of the ETIC. The numerical solution that includes the ETIC shows significantly improved skill compared to the solution that does not include the ETIC. For the M2 constituent, the largest tidal frequency in the SAB, overall amplitude and phase error is reduced from 0.25 m to 0.03 m and 13.8o to 2.8o for coastal observation stations. Similar improvement is shown for midshelf stations. Diurnal tides are relatively unaffected by the ETIC.

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