Modeling and analysis of internal-tide generation and beamlike onshore propagation in the vicinity of shelfbreak canyons
Zhang, Weifeng G.
Duda, Timothy F.
Udovydchenkov, Ilya A.
MetadataShow full item record
KeywordCirculation/ Dynamics; Baroclinic flows; Internal waves; Ocean circulation; Topographic effects; Waves, oceanic; Models and modeling; Numerical analysis/modeling
A hydrostatic numerical model with alongshore-uniform barotropic M2 tidal boundary forcing and idealized shelfbreak canyon bathymetries is used to study internal-tide generation and onshore propagation. A control simulation with Mid-Atlantic Bight representative bathymetry is supported by other simulations that serve to identify specific processes. The canyons and adjacent slopes are transcritical in steepness with respect to M2 internal wave characteristics. Although the various canyons are symmetrical in structure, barotropic-to-baroclinic energy conversion rates Cυ are typically asymmetrical within them. The resulting onshore-propagating internal waves are the strongest along beams in the horizontal plane, with the stronger beam in the control simulation lying on the side with higher Cυ. Analysis of the simulation results suggests that the cross-canyon asymmetrical Cυ distributions are caused by multiple-scattering effects on one canyon side slope, because the phase variation in the spatially distributed internal-tide sources, governed by variations in the orientation of the bathymetry gradient vector, allows resonant internal-tide generation. A less complex, semianalytical, modal internal wave propagation model with sources placed along the critical-slope locus (where the M2 internal wave characteristic is tangent to the seabed) and variable source phasing is used to diagnose the physics of the horizontal beams of onshore internal wave radiation. Model analysis explains how the cross-canyon phase and amplitude variations in the locally generated internal tides affect parameters of the internal-tide beams. Under the assumption that strong internal tides on continental shelves evolve to include nonlinear wave trains, the asymmetrical internal-tide generation and beam radiation effects may lead to nonlinear internal waves and enhanced mixing occurring preferentially on one side of shelfbreak canyons, in the absence of other influencing factors.
Author Posting. © American Meteorological Society, 2014. 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 Physical Oceanography 44 (2014): 834-849, doi:10.1175/JPO-D-13-0179.1.
Suggested CitationArticle: Zhang, Weifeng G., Duda, Timothy F., Udovydchenkov, Ilya A., "Modeling and analysis of internal-tide generation and beamlike onshore propagation in the vicinity of shelfbreak canyons", Journal of Physical Oceanography 44 (2014): 834-849, DOI:10.1175/JPO-D-13-0179.1, https://hdl.handle.net/1912/6605
Showing items related by title, author, creator and subject.
Frank, Scott D.; Badiey, Mohsen; Lynch, James F.; Siegmann, William L. (Acoustical Society of America, 2004-12)To investigate acoustic effects of nonlinear internal waves, the two southwest tracks of the SWARM 95 experiment are considered. An airgun source produced broadband acoustic signals while a packet of large nonlinear internal ...
A coupled-mode shallow-water model for tidal analysis : internal tide reflection and refraction by the Gulf Stream Kelly, Samuel M.; Lermusiaux, Pierre F. J.; Duda, Timothy F.; Haley, Patrick J. (American Meteorological Society, 2016-12-14)A hydrostatic, coupled-mode, shallow-water model (CSW) is described and used to diagnose and simulate tidal dynamics in the greater Mid-Atlantic Bight region. The reduced-physics model incorporates realistic stratification ...
Morozov, Andrey K.; Colosi, John A. (Acoustical Society of America, 2005-03)Parabolic equation numerical simulations of waveguide acoustical beam propagation in an ocean of Garrett–Munk internal waves are used to examine the range evolution of beam properties such as beamwidth (both spectral and ...