On the parametrizations for the dissipation rate of the turbulence kinetic energy in stable conditions

Observations acquired in the stable surface layer during two field experiments (The Mountain Terrain Atmospheric Modeling and Observations Program and the Climate Change Tower Integrated Project) are considered to test different parametrizations of the dissipation rate of turbulence kinetic energy (TKE). Particular attention is dedicated to the effect of the submeso motions on these parametrizations. The analysis shows that TKE-based formulations are particularly prone to the submeso effect, while better results are obtained if the vertical velocity variance is considered. In the latter case, stability must be taken into account explicitly in Mellor-Yamada type parametrizations but not in shear-based formulations.