Rollover, drowning, and discontinuous retreat: Distinct modes of barrier response to sea-level rise arising from a simple morphodynamic model
MetadataShow full item record
KeywordBarrier Evolution; Sea-level rise; Shoreface Dynamics; Barrier Drowning; Discontinuous Retreat; Rollover
We construct a simple morphodynamic model to investigate the long-term dynamic evolution of a coastal barrier system experiencing sea-level rise. Using a simplified barrier geometry, the model includes a dynamic shoreface profile that can be out of equilibrium and explicitly treats barrier sediment overwash as a flux. With barrier behavior primarily controlled by the maximum potential overwash flux and the rate of shoreface response, the modeled barrier system demonstrates four primary behaviors: height drowning, width drowning, constant landward retreat, and a periodic retreat. Height drowning occurs when overwash fluxes are insufficient to maintain the landward migration rate required to keep pace with sea-level rise. On the other hand, width drowning occurs when the shoreface response rate is insufficient to maintain the barrier geometry during overwash-driven landward migration. During periodic barrier retreat, the barrier experiences oscillating periods of rapid overwash followed by periods of relative stability as the shoreface resteepens. This periodic retreat, which occurs even with a constant sea-level rise rate, arises when overwash rates and shoreface response rates are large and of similar magnitude. We explore the occurrence of these behaviors across a wide range of parameter values and find that in addition to the maximum overwash flux and the shoreface response rate, barrier response can be particularly sensitive to the sea-level rise rate and back-barrier lagoon slope. Overall, our findings contrast with previous research which has primarily associated complex barrier behavior with changes in external forcing such as sea-level rise rate, sediment supply, or back-barrier geometry.
Author Posting. © American Geophysical Union, 2014. 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: Earth Surface 119 (2014): 779–801, doi:10.1002/2013JF002941.
Suggested CitationArticle: Lorenzo-Trueba, Jorge, Ashton, Andrew D., "Rollover, drowning, and discontinuous retreat: Distinct modes of barrier response to sea-level rise arising from a simple morphodynamic model", Journal of Geophysical Research: Earth Surface 119 (2014): 779–801, DOI:10.1002/2013JF002941, https://hdl.handle.net/1912/6714
Showing items related by title, author, creator and subject.
Effects of sea-level rise on barrier island groundwater system dynamics – ecohydrological implications Masterson, John P.; Fienen, Michael N.; Thieler, E. Robert; Gesch, Dean B.; Gutierrez, Benjamin T.; Plant, Nathaniel G. (John Wiley & Sons, 2014-11-12)We used a numerical model to investigate how a barrier island groundwater system responds to increases of up to 60 cm in sea level. We found that a sea-level rise of 20 cm leads to substantial changes in the depth of the ...
Coupling instrumental and geological records of sea-level change : evidence from southern New England of an increase in the rate of sea-level rise in the late 19th century Donnelly, Jeffrey P.; Cleary, Peter; Newby, Paige E.; Ettinger, Robert (American Geophysical Union, 2004-03-11)We construct a high-resolution relative sea-level record for the past 700 years by dating basal salt-marsh peat samples above a glacial erratic in an eastern Connecticut salt marsh, to test whether or not the apparent ...
The Kuroshio Extension : a leading mechanism for the seasonal sea-level variability along the west coast of Japan Ma, Chao; Yang, Jiayan; Wu, Dexing; Lin, Xiaopei (2009-10-08)Sea level changes coherently along the two coasts of Japan on the seasonal time scale. AVISO satellite altimetry data and OFES (OGCM for the Earth Simulator) results indicate that the variation propagates clockwise from ...