Alongshore momentum balance analysis on a cuspate foreland
List, Jeffrey H.
Warner, John C.
MetadataShow full item record
KeywordVortex force; Advective acceleration; Diamond Shoals; Subtidal flows; Breaking acceleration; Curved coastline
Nearshore measurements of waves and currents off Cape Hatteras, North Carolina, U.S.A, are used to investigate depth-averaged subtidal circulation and alongshore momentum balances in the surf and inner shelf region around a cuspate foreland. Data were collected on both sides of the cape representing shorefaces with contrasting shoreline orientation (north-south vs. northwest-southeast) subjected to the same wind forcing. In the nearshore, the subtidal flow is aligned with the local coastline orientation while at the cape point the flow is along the existing submerged shoal, suggesting that cape associated shoals may act as an extension of the coastline. Alongshore momentum balance analysis incorporating wave-current interaction by including vortex and Stokes-Coriolis forces reveals that in deep waters surface and bottom stress are almost in balance. In shallower waters, the balance is complex as nonlinear advection and vortex force become important. Furthermore, linearized momentum balance analysis suggests that the vortex force can be of the same order as wind and wave forcing. Farther southwest of Cape Hatteras point, wind and wave forcing alone fail to fully explain subtidal flow variability and it is shown that alongshore pressure gradient as a response to the wind forcing can close the momentum balance. Adjacent tide gauge data suggest that the magnitude of pressure gradient depends on the relative orientation of local coastline to the wind vector, and in a depth-averaged sense the pressure gradient generation due to change in coastline orientation even at km length scale is analogous to the effect of alongshore variable winds on a straight coastline.
Author Posting. © American Geophysical Union, 2013. 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 118 (2013): 5280–5295, doi:10.1002/jgrc.20358.
Showing items related by title, author, creator and subject.
Asper, Vernon L. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1985-12)Samples from time-series sediment traps deployed in three distinct oceanographic settings (North Pacific, Panama Basin, and Black Sea) provide strong evidence for rapid settling of marine particles by aggregates. Particle ...
DeCarlo, Thomas M.; Cohen, Anne L.; Barkley, Hannah C.; Cobban, Quinn; Young, Charles W.; Shamberger, Kathryn E. F.; Brainard, Russell E.; Golbuu, Yimnang (2014-10)Coral reefs exist in a delicate balance between calcium carbonate (CaCO3) production and CaCO3 loss. Ocean acidification (OA), the CO2-driven decline in seawater pH and CaCO3 saturation state (Ω), threatens to tip this ...
von Reden, Karl F.; Zhang, Mei; Meigs, Martha; Sichel, Enid; Fang, Shaoli; Baughman, Ray H. (2007-03)Carbon nanotube technology has rapidly advanced in recent years, making it possible to create meter-long, ~4 cm wide films of multi-walled tubes of less than 3 μg/cm2 areal density in a bench top open-air procedure . ...