Influence of two tropical storms on the residual flow in a subtropical tidal inlet

TitleInfluence of two tropical storms on the residual flow in a subtropical tidal inlet
Publication TypeJournal Article
Year of Publication2013
AuthorsWaterhouse A.F, Tutak B., Valle-Levinson A., Sheng Y.P
JournalEstuaries and Coasts
Date Published2013/09
Type of ArticleArticle
ISBN Number1559-2723
Accession NumberWOS:000323248500013
Keywordschesapeake bay; circulation; coastal-plain estuary; currents; exchange; partially-mixed estuary; relative importance; Residual circulation; rotating basin; sea; St. Augustine Inlet; subtidal; Tidal inlets; Tropical storms; variability

The mechanisms responsible for the modulation of laterally sheared non-tidal (residual) exchange flow in a subtropical inlet, with special emphasis on tropical storm influence, are studied using a combination of current velocity profiles and hydrographic and meteorological data. The mouth of the inlet, St. Augustine Inlet in northeast Florida, is characterized by a 15-m-deep channel flanked by shoals (< 6 m deep). Residual flows across the inlet mouth were laterally sheared with inflow in the channel and outflow over the shoals. This pattern persisted during four separate semi-diurnal tidal cycle surveys effected over 3 years. During spring tides, residual exchange flows intensified relative to neap tides. Residual inflow in the channel only reversed immediately after tropical storms because of their extreme winds and major temporal changes in water level. After the residual flow reversed in the channel, along-channel baroclinicity drove gravitational circulation that persisted for 4.5 days and was enhanced by offshore winds. A depth-averaged along-basin momentum budget highlighted the importance of bottom friction to help balance the barotropic pressure gradient. The rest of the momentum budget was likely provided by advective terms. During and after tropical storms, accelerations from wind stress and baroclinic pressure gradients also became influential in the along-basin momentum budget.

Short TitleEstuaries Coasts
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