A TKE-DISSIPATION MODEL FOR THE ATMOSPHERIC BOUNDARY-LAYER

The dissipation, epsilon, of turbulent kinetic energy (TKE) is a key parameter in atomospheric boundary-layer (ABL) models. Besides being a sink for momentum, it is often used together with the TKE to define an internal turbulence time scale for closure relations. A prognostic formulation for the dissipation of TKE is formulated, based on isotropic tensor modeling methods. The formulation is coupled to a level 2.5 second-order closure model and evaluated against measurements taken in horizontally homogeneous conditions, as well as against a tailored length-scale formulation. A formulation suitable for conyective as well as neutral and stable ABLs is suggested.