Direct estimation of the Reynolds stress vertical structure in the nearshore
MetadataShow full item record
Measurements of the vertical Reynolds stress components in the wave-dominated nearshore are required to diagnose momentum and turbulence dynamics. Removing wave bias from Reynolds stress estimates is critical to a successful diagnosis. Here two existing Reynolds stress estimation methods (those of Trowbridge, and Shaw and Trowbridge) for wave-dominated environments and an extended method (FW) that is a combination of the two are tested with a vertical array of three current meters deployed in 3.2-m water depth off an ocean beach. During the 175-h-long experiment the instruments were seaward of the surfzone and the alongshore current was wind driven. Intercomparison of Reynolds stress methods reveals that the Trowbridge method is wave bias dominated. Tests of the integrated cospectra are used to reject bad Reynolds stress estimates, and the Shaw and Trowbridge estimates are rejected more often than FW estimates. With the FW method, wave bias remains apparent in the cross-shore component of the Reynolds stress. However, the alongshore component of Reynolds stress measured at the three current meters are related to each other with a vertically uniform first EOF containing 73% of the variance, indicating the presence of a constant stress layer. This is the first time the vertical structure of Reynolds stress has been measured in a wave-dominated environment. The Reynolds stress is, albeit weakly, related to the wind stress and a parameterized bottom stress. Using derived wave bias and bottom stress parameterizations, the effect of wave bias on Reynolds stress estimates is shown to be weaker for more typical surfzone conditions (with both stronger waves and currents than those observed here).
Author Posting. © American Meteorological Society, 2007. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 24 (2007): 102-116, doi:10.1175/JTECH1953.1.
Suggested CitationJournal of Atmospheric and Oceanic Technology 24 (2007): 102-116
Showing items related by title, author, creator and subject.
Characterizing wave- and current- induced bottom shear stress : U.S. middle Atlantic continental shelf Dalyander, P. Soupy; Butman, Bradford; Sherwood, Christopher R.; Signell, Richard P.; Wilkin, John L. (Elsevier B.V., 2012-11-05)Waves and currents create bottom shear stress, a force at the seabed that influences sediment texture distribution, micro-topography, habitat, and anthropogenic use. This paper presents a methodology for assessing the ...
12 May 2008 M = 7.9 Wenchuan, China, earthquake calculated to increase failure stress and seismicity rate on three major fault systems Toda, Shinji; Lin, Jian; Meghraoui, Mustapha; Stein, Ross S. (American Geophysical Union, 2008-09-09)The Wenchuan earthquake on the Longmen Shan fault zone devastated cities of Sichuan, claiming at least 69,000 lives. We calculate that the earthquake also brought the Xianshuihe, Kunlun and Min Jiang faults 150–400 km from ...
On the calculation of wind stress curl over open ocean areas from synoptic meteorological data with application to time dependent ocean circulation Welch, Christopher Slocombe (Woods Hole Oceanographic Institution, 1972-02)The method used by N. P. Fofonoff for estimating wind stress curl from surface atmospheric pressure maps is developed for use with the National Meterological Center analysis grid. A formula is developed relating the wind ...