Variable behavior in pycnocline mixing over shelf seas

Vertical mixing, driven by turbulence in the ocean, underpins many of the critical interactions that allow life on earth to flourish since vertical buoyancy flux maintains global overturning circulation and vertical nutrient fluxes are critical to primary production. Prediction of the ocean system is therefore dependent on accurate simulation of turbulent processes that, by their very nature, are chaotic. A growing evidence base exists that provides insight into these complex processes and permits investigation of turbulence relative to better determined, and therefore predictable, parameters. Here we examine three time series of the dissipation rate of turbulent kinetic energy (ε) in “stability space”. We reveal an ordered structure within the mean distribution of ε that compares well to a variety of proposed models of oceanic turbulence. The requirement for differing site-specific tuning and only partial success however raises questions over “missing physics” within such models and the validity of measurement techniques.