Peer-Reviewed Journal Details
Mandatory Fields
Sutherland, G.; Christensen, K.H.; and Ward, B.
2014
March
Journal Of Geophysical Research-Oceans
Evaluating Langmuir turbulence parameterizations in the ocean surface boundary layer
Published
Altmetric: 2WOS: 20 ()
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Langmuir turbulence ocean surface boundary layer dissipation of turbulent kinetic energy LARGE-EDDY SIMULATION MIXED-LAYER BREAKING WAVES CIRCULATIONS DISSIPATION WIND EDDIES DRIVEN DRIFT
119
1899
1910
It is expected that surface gravity waves play an important role in the dynamics of the ocean surface boundary layer (OSBL), quantified with the turbulent Langmuir number (La-root u(*)/u(s0), where u(*) and u(s0) are the friction velocity and surface Stokes drift, respectively). However, simultaneous measurements of the OSBL dynamics along with accurate measurements of the wave and atmospheric forcing are lacking. Measurements of the turbulent dissipation rate E were collected using the Air-Sea Interaction Profiler (ASIP), a freely rising microstructure profiler. Two definitions for the OSBL depth are used: the mixed layer derived from measurements of density (h(rho)), and the mixing layer (h(epsilon)) determined from direct measurements of epsilon. When surface buoyancy forces are relatively small, epsilon proportional to La-2 only near the surface with no dependency on La at mid-depths of the OSBL when using h(rho) as the turbulent length scale. However, if h(epsilon) is used then the dependence of epsilon with La-2 is more uniform throughout the OSBL. For relatively high destabilizing surface buoyancy forces, epsilon is proportional to the ratio of the OSBL depth against the Langmuir stability length L-L. During destabilizing conditions, the mixed and mixing layer depths are nearly identical, but we have relatively few measurements under these conditions, rather than any physical implications. Observations of epsilon are compared with the OSBL regime diagram of Belcher et al. (2012) and are generally within an order of magnitude, but there is an improved agreement if h(epsilon) is used as the turbulent length scale rather than h(rho).
10.1002/2013JC009537
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