Erlangen 2018 – scientific programme

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UP: Fachverband Umweltphysik

UP 6: Oceanography

UP 6.1: Invited Talk

Tuesday, March 6, 2018, 16:30–17:00, G 1.011

Simple relations for mixing in estuaries — •Hans Burchard — Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany

The Knudsen and Total Exchange Flow (TEF) theories derived from the conservation laws of mass and salt by applying Gauss' theorem to the volume of a confined estuarine or marginal sea basin provide a quantitative understanding for estuarine physics. These theories represent exchange flows across an open boundary to the adjacent ocean in terms of bulk values (Knudsen theory: inflow and outflow volume or salinity) or with resolution in salinity space (TEF: profiles of volume and salt flux in salinity coordinates). Here, these theories are extended towards mixing of salinity, defined as the decay of salinity variance due to turbulent mixing. These new Knudsen and TEF relations for mixing are derived by applying Gauss' theorem to the salinity variance equation. As a result, long-term averaged mixing in estuaries and marginal seas can be estimated by simply considering inflowing and outflowing salinities at the open boundary as well as net freshwater run-off.