Regensburg 2007 – scientific programme

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UP: Fachverband Umweltphysik

UP 4: Ozeanographie, Hydro- und Kryosphäre

UP 4.1: Invited Talk

Monday, March 26, 2007, 11:30–12:00, H48

Ocean mixing: why it's important and how it's measured by tracer release experiments — •Andrew Watson — School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK

The ocean is a stratified medium nearly everywhere, with vertical mixing across density surfaces many orders of magnitude slower than horizontal mixing. Measuring the rate of mixing has proved difficult, because it is episodic, and varies by orders of magnitude depending on location. Yet the integrated effect of mixing is critical for our understanding of the global ocean circulation, determining in particular how the the deep ocean is ventilated -- brought to the surface and returned to depth.

In the last dozen or so years a small number of large scale experiments using releases of sulphur hexafluoride, an inert tracer that can be detected at very low concentration in sea water, have provided accurate estimates of mixing rates integrated over large regions of the ocean the first time. These experiments have enabled us to construct a coherent picture of how the ocean mixes. This talk will review how these experiments have been done and their most important results.