Analysis of Near-Surface Oceanic Measurements Obtained During CBLAST-Low
2009
Plueddemann, Albert J. | Trowbridge, John H.
Measurements obtained during the low-wind component of the Coupled Boundary Layers and Air-Sea Transfer program (CBLAST-Low) were used to elucidate the energetics of the ocean surface boundary layer. This work addressed the closure of the turbulent kinetic energy (TKE) budget, the relationship between TKE and dissipation, and the roles of wave breaking and Langmuir circulation in controlling turbulent diffusivity. The measurements occurred primarily during conditions in which shear, buoyancy and wave breaking were important energy sources while Langmuir circulation was present but not dominant. The primary results were (l) The observed dissipation rate of TKE was enhanced relative that expected near a rigid boundary, and in good agreement with a scaling which assumes that TKE is extracted from the surface waves via breaking and dissipates as it is transported downward, (2) The dissipation rate of TKE was not balanced by local production or growth, indicating that the divergence of the flux of TKE was important, (3) The vertical distribution of TKE was reasonably well explained by a one-dimensional model incorporating the effects of surface gravity waves and shear instabilities, (4) Langmuir circulation did not appear to play a distinct role in boundary layer energetics.
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