Anatomy of a turbulent patch in a large shallow lake

Leon Boegman, Damien Bouffard
VIII th Int. Symp. on Stratified Flows   unpublished
Temperature microstructure casts are often analyzed to compute the diapycnal diffusivity K ρ in geophysical flows. In the present study, we analyze 17 microstructure casts obtained during a Kelvin-Helmholtz billowing event at the base of the upper mixed layer in Lake Erie. From these casts, the turbulence properties of the mixing event are investigated and six parameterizations are applied to determine K ρ. In comparison to the Osborn-Cox method, the four-equation overturn Froude number í µí°¹í
more » ... oude number í µí°¹í µí±Ÿ # vs. overturn Reynolds number í µí±í µí±’ # parameterization and the four-equation buoyancy Reynolds number í µí±í µí±’ & parameterization were found to be most accurate. Models with fixed mixing efficiency Γ = 0.2 performed poorly. From these data, we speculate that the transition to the Energetic Regime at high í µí±í µí±’ & may occur when í µí°¹í µí±Ÿ # ~ 1, giving í µí±í µí±’ & ~ í µí°¹í µí±Ÿ #. í µí±í µí±’ # ~ í µí±í µí±’ # .