Improving the Eddy Kinetic Energy model for planetary boundary layer description

Results from a third-order turbulence closure scheme model and from experimental studies are used to improve the Eddy Kinetic Energy (EKE) model for the Planetary Boundary Layer (PBL). It is proposed to use two different lengths, one for mixing and one for dissipation, as well as a temperature counter-gradient in the heat flux parameterization and a corrective term in the gradient-type relation for the computation of EKE flux. Such refinements do not lead to any increase in computing cost nor to any particular difficulty for the model implementation. They however allow for significantly better results, which are in close agreement with those of much more sophisticated models, at least in the case of the convective PBL, which is mainly considered here.