Abstract

Measuring the rate of vertical mixing in the interior of the density-stratified ocean is essential to determining the distribution of heat, biologically important nutrients and the fate of pollutants. As demonstrated by Munk (1966) in his “Abyssal Recipes” paper, we know the rate of mixing controls the nature of the abyssal circulation and thus ocean mixing is dynamically important on both short and long timescales. The history of making measurements of mixing dates back over 50 years and the principle tool has been free-falling turbulent microstructure profilers. The interpretation of these measurements remains a subject of debate, however, and the talk will discuss three different methods that have been proposed to interpret microstructure measurements. We will also compare profiler measurements with measurements from fixed moorings. Moorings have the potential of offering long records of mixing over the entire water column and thus one means of increasing the amount of measurements which, despite 50 years of effort, still remain relatively scarce.