M4: Entropy production in turbulence parameterisations
Principal investigators: Dr. Almut Gassmann (Institute for Atmospheric Sciences Rostock), Prof. Valerio Lucarini (Universität Hamburg), Dr. Richard Blender (Universität Hamburg)
We aim at a modification of sub-scale parameterisation schemes for heat, buoyancy, and momentum fluxes which are associated with energy dissipation and internal entropy production. We assess existing parameterisation schemes in view of the second law of thermodynamics and aim at their modification to conform with this law. Additionally, we wish to deal with the statistical mechanical fluctuations occurring on small scales, which can lead to temporary negative diffusion coefficients in sub-grid parameterisations. An outcome is the combination of dissipation and backscatter in a unified approach.