Barrier island breach evolution : alongshore transport and bay-ocean pressure gradient interactions
MetadataShow full item record
Physical processes controlling repeated openings and closures of a barrier island breach between a bay and the open ocean are studied using aerial photographs and atmospheric and hydrodynamic observations. The breach site is located on Pea Island along the Outer Banks, separating Pamlico Sound from the Atlantic Ocean. Wind direction was a major control on the pressure gradients between the bay and the ocean to drive flows that initiate or maintain the breach opening. Alongshore sediment flux was found to be a major contributor to breach closure. During the analysis period from 2011 to 2016, three hurricanes had major impacts on the breach. First, Hurricane Irene opened the breach with wind-driven flow from bay to ocean in August 2011. Hurricane Sandy in October 2012 quadrupled the channel width from pressure gradient flows due to water levels that were first higher on the ocean side and then higher on the bay side. The breach closed sometime in Spring 2013, most likely due to an event associated with strong alongshore sediment flux but minimal ocean-bay pressure gradients. Then, in July 2014, Hurricane Arthur briefly opened the breach again from the bay side, in a similar fashion to Irene. In summary, opening and closure of breaches are shown to follow a dynamic and episodic balance between along-channel pressure gradient driven flows and alongshore sediment fluxes.
Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 121 (2016): 8720–8730, doi:10.1002/2016JC012029.
Suggested CitationJournal of Geophysical Research: Oceans 121 (2016): 8720–8730
Showing items related by title, author, creator and subject.
Connolly, Thomas P.; Hickey, Barbara M.; Shulman, Igor; Thomson, Richard E. (American Meteorological Society, 2014-01)The California Undercurrent (CUC), a poleward-flowing feature over the continental slope, is a key transport pathway along the west coast of North America and an important component of regional upwelling dynamics. This ...
Inundation of a barrier island (Chandeleur Islands, Louisiana, USA) during a hurricane : observed water-level gradients and modeled seaward sand transport Sherwood, Christopher R.; Long, Joseph W.; Dickhudt, Patrick J.; Dalyander, P. Soupy; Thompson, David M.; Plant, Nathaniel G. (John Wiley & Sons, 2014-07-15)Large geomorphic changes to barrier islands may occur during inundation, when storm surge exceeds island elevation. Inundation occurs episodically and under energetic conditions that make quantitative observations difficult. ...
Acceleration of a stratified current over a sloping bottom, driven by an alongshelf pressure gradient Chapman, David C.; Lentz, Steven J. (American Meteorological Society, 2005-08)An idealized theoretical model is developed for the acceleration of a two-dimensional, stratified current over a uniformly sloping bottom, driven by an imposed alongshelf pressure gradient and taking into account the effects ...