Suppression of internal wave breaking in the Antarctic Circumpolar Current near topography
Waterman, Stephanie N.
Polzin, Kurt L.
Naveira Garabato, Alberto C.
Sheen, Katy L.
MetadataShow full item record
KeywordCirculation/ Dynamics; Diapycnal mixing; Internal waves; Small scale processes; Turbulence; Observational techniques and algorithms; In situ oceanic observations; Profilers, oceanic
Simultaneous full-depth microstructure measurements of turbulence and finestructure measurements of velocity and density are analyzed to investigate the relationship between turbulence and the internal wave field in the Antarctic Circumpolar Current. These data reveal a systematic near-bottom overprediction of the turbulent kinetic energy dissipation rate by finescale parameterization methods in select locations. Sites of near-bottom overprediction are typically characterized by large near-bottom flow speeds and elevated topographic roughness. Further, lower-than-average shear-to-strain ratios indicative of a less near-inertial wave field, rotary spectra suggesting a predominance of upward internal wave energy propagation, and enhanced narrowband variance at vertical wavelengths on the order of 100 m are found at these locations. Finally, finescale overprediction is typically associated with elevated Froude numbers based on the near-bottom shear of the background flow, and a background flow with a systematic backing tendency. Agreement of microstructure- and finestructure-based estimates within the expected uncertainty of the parameterization away from these special sites, the reproducibility of the overprediction signal across various parameterization implementations, and an absence of indications of atypical instrument noise at sites of parameterization overprediction, all suggest that physics not encapsulated by the parameterization play a role in the fate of bottom-generated waves at these locations. Several plausible underpinning mechanisms based on the limited available evidence are discussed that offer guidance for future studies.
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): 1466–1492, doi:10.1175/JPO-D-12-0154.1.
Showing items related by title, author, creator and subject.
Observationally constrained modeling of sound in curved ocean internal waves: Examination of deep ducting and surface ducting at short range Duda, Timothy F.; Lin, Ying-Tsong; Reeder, D. Benjamin (Acoustical Society of America, 2011-09)A study of 400 Hz sound focusing and ducting effects in a packet of curved nonlinear internal waves in shallow water is presented. Sound propagation roughly along the crests of the waves is simulated with a three-dimensional ...
Observed limiting cases of horizontal field coherence and array performance in a time-varying internal wavefield Collis, Jon M.; Duda, Timothy F.; Lynch, James F.; DeFerrari, Harry A. (Acoustical Society of America, 2008-08-28)Using a moored source and horizontal/vertical line array combination, horizontal coherence properties of high signal to noise ratio (>=20 dB) 100–1600 Hz signals have been measured. Internal waves in the area of the ...
Scotti, Alberto; Pineda, Jesus (American Geophysical Union, 2004-11-25)We report on near-bottom waves of elevation with amplitude nearly half the 25 m water column, very steep, and propagating into a sheared turbulent wave-guide. The waves contained trapped cores transporting parcels of water ...