Characterization and modulation of Langmuir circulation in Chesapeake Bay
Scully, Malcolm E.
Fisher, Alexander W.
Suttles, Steven E.
Sanford, Lawrence P.
Boicourt, William C.
MetadataShow full item record
KeywordCirculation/ Dynamics; Convection; Instability; Mixing; Turbulence; Wave breaking; Wind stress
Measurements made as part of a large-scale experiment to examine wind-driven circulation and mixing in Chesapeake Bay demonstrate that circulations consistent with Langmuir circulation play an important role in surface boundary layer dynamics. Under conditions when the turbulent Langmuir number Lat is low (<0.5), the surface mixed layer is characterized by 1) elevated vertical turbulent kinetic energy; 2) decreased anisotropy; 3) negative vertical velocity skewness indicative of strong/narrow downwelling and weak/broad upwelling; and 4) strong negative correlations between low-frequency vertical velocity and the velocity in the direction of wave propagation. These characteristics appear to be primarily the result of the vortex force associated with the surface wave field, but convection driven by a destabilizing heat flux is observed and appears to contribute significantly to the observed negative vertical velocity skewness. Conditions that favor convection usually also have strong Langmuir forcing, and these two processes probably both contribute to the surface mixed layer turbulence. Conditions in which traditional stress-driven turbulence is important are limited in this dataset. Unlike other shallow coastal systems where full water column Langmuir circulation has been observed, the salinity stratification in Chesapeake Bay is nearly always strong enough to prevent full-depth circulation from developing.
Author Posting. © American Meteorological Society, 2015. 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 45 (2015): 2621–2639, doi:10.1175/JPO-D-14-0239.1.
Suggested CitationJournal of Physical Oceanography 45 (2015): 2621–2639
Showing items related by title, author, creator and subject.
Richardson, Philip L. (2007-07-23)Recent global warming caused by humans and the prediction of a reduced Atlantic Ocean meridional overturning circulation in the future has increased interest in the role of the overturning circulation in climate change. ...
Spreading of Denmark Strait overflow water in the western subpolar North Atlantic : insights from eddy-resolving simulations with a passive tracer Xu, Xiaobiao; Rhines, Peter B.; Chassignet, Eric P.; Schmitz, William J. (American Meteorological Society, 2015-12)The oceanic deep circulation is shared between concentrated deep western boundary currents (DWBCs) and broader interior pathways, a process that is sensitive to seafloor topography. This study investigates the spreading ...
Kamenkovich, Igor V.; Rypina, Irina I.; Berloff, Pavel S. (American Meteorological Society, 2015-03)This study examines anisotropic transport properties of the eddying North Atlantic flow, using an idealized model of the double-gyre oceanic circulation and altimetry-derived velocities. The material transport by the ...