Large-eddy simulations of the baroclinic mixed layer

The effects of baroclinicity, imposed on the dry mixed layer by the presence of large-scale, horizontal temperature gradients, have been investigated based on a large-eddy simulation model. The purpose of this investigation is to examine simultaneous impacts of thermal stratification and shear in the atmospheric boundary layer. For this purpose, five cases are considered - one barotropic, and four baroclinic. Based on the performed simulations, a new parametrization of the interfacial layer is proposed. The parameterization employs new interfacial scaling, which is valid at the top of the mixed layer. In terms of new scales, dimensionless moments characterizing turbulence at the top of the shearless mixed layer are universal constants. In the sheared case, dimensionless statistics of turbulence are shown to be functions of the interfacial Richardson number.