Inspired on the Transilient Turbulence Theory, mixing matrices for 3 classical Planetary Boundary layer regimes are obtained. The method proposed by Ebert, Schumann and Stull (JAS 46, 2178-2207, 1989) is followed, but with larger resolution.
The Meso-NH model is used in LES configuration. The turbulence scheme uses variable Schmidt numbers for the turbulent subgrid mixing of scalars. Three classical LES intercomparison cases are made, introducing a different scalar at each model level, once the turbulence is well established. The concentration of every scalar after a certain time illustrates the way the LES diffuses the different scalars.
This is made for a Convective Boundary Layer, a Neutrally stratified shear-driven PBL and for a Smoke-Cloud case, which emulates a Stratocumulus cloud deck. The shape of the matrices is inspected according to the characteristic time scale of each flow and a comparative study between the cases is presented. The resulting matrices can be used as validation tools for further improvements of the Transilient Turbulent Theory, as well as for other type of closures, following the proposal of Cuxart et al (BLM 67, 251-276, 1994)