Momentum balances on the inner continental shelf at Martha's Vineyard Coastal Observatory
MetadataShow full item record
The subtidal, depth-average momentum balances in 12 m and 27 m water depth are investigated using observations from 2001 to 2007 of water velocity, temperature, and density; bottom pressure; surface gravity waves; and wind stress. In the fluctuating across-shelf momentum budget, the dominant terms are surface wind stress, pressure gradient, and Coriolis acceleration. The balance is a combination of (1) the geostrophic balance expected at midshelf sites and (2) the coastal setup and setdown balance driven by the across-shelf wind stress expected where surface and bottom boundary layers overlap. At the 12 m site, the estimated wave radiation stress gradient due to surface gravity wave shoaling is also large but is uncorrelated with the observed pressure gradient. A simple model suggests the wave radiation stress gradient is balanced by an across-shelf pressure gradient with a spatial scale too small to resolve with this mooring array. In the fluctuating along-shelf momentum balance, the dominant terms are surface wind stress, pressure gradient, and bottom stress at the shallower site, but the other estimated terms are not negligible. Our results support the Grant and Madsen (1986) formulation for wave-induced bottom stress. The fluctuating along-shelf pressure gradient is mainly a local sea level response to wind forcing, not a remotely generated pressure gradient. A strong correlation between along-shelf velocity and along-shelf wind stress at the shallower site is captured by a simple steady model of imbalance between wind stress and pressure gradient balanced by linear bottom drag.
Author Posting. © American Geophysical Union, 2010. 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 115 (2010): C12023, doi:10.1029/2009JC005578.
Suggested CitationArticle: Fewings, Melanie R., Lentz, Steven J., "Momentum balances on the inner continental shelf at Martha's Vineyard Coastal Observatory", Journal of Geophysical Research 115 (2010): C12023, DOI:10.1029/2009JC005578, https://hdl.handle.net/1912/4303
Showing items related by title, author, creator and subject.
Cross-shelf circulation and momentum and heat balances over the inner continental shelf near Martha's Vineyard, Massachusetts Fewings, Melanie R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-09)The water circulation and evolution of water temperature over the inner continental shelf are investigated using observations of water velocity, temperature, density, and bottom pressure; surface gravity waves; wind ...
Temporal evolution of the momentum balance terms and frictional adjustment observed over the inner shelf during a storm Grifoll, Manel; Aretxabaleta, Alfredo L.; Pelegri, Josep L.; Espino, Manuel (Copernicus Publications on behalf of the European Geosciences Union, 2016-01-18)We investigate the rapidly changing equilibrium between the momentum sources and sinks during the passage of a single two-peak storm over the Catalan inner shelf (NW Mediterranean Sea). Velocity measurements at 24 m water ...
Coastal ocean processes inner-shelf study : coastal and moored physical oceanographic measurements Alessi, Carol A.; Lentz, Steven J.; Austin, Jay A. (Woods Hole Oceanographic Institution, 1996-05)To improve our understanding of the physical and biological processes influencing plantonic larval distributions over the inner shelf, an interdisciplinary field program funded by the National Science Foundation's Coastal ...