Turbulent length scales in a fast-flowing, weakly stratified, strait: Cook Strait, New Zealand

[摘要] There remains much to be learned about the full range of turbulent motions in the ocean. Here we consider turbulence and overturn scales in the relatively shallow, weakly stratified, fast-flowing tidal flows of Cook Strait, New Zealand. With flow speeds reaching 3 m s ⁻¹ in a water column of ∼300 m depth the location is heuristically known to be highly turbulent. Dissipation rates of turbulent kinetic energy ε , along with the Thorpe scale, L_T , are described. Thorpe scales, often as much as one-quarter of the water depth, are compared with dissipation rates and background flow speed. Turbulent energy dissipation rates ε are modest but high for oceans, around 5 × 10 - 5 W kg ⁻¹ . Comparison of the buoyancy-limit Ozmidov scale L_Oz suggest the Cook Strait data lie for the majority of the time in the L_Oz > L_T regime, but not universally. Also, comparison of direct and L_T -based estimates of ε exhibit reasonable similarity.

[学科分类] 海洋学与技术