Vertical turbulence diffusivity for weak or strong stable stratification

A theoretical relation is derived for the vertical turbulent diffusivity K_zz in weak as well as strong stable stratification. This relation expresses K_zz in terms of the buoyancy frequency (Brunt-Väisälä frequency), the energy dissipation rate ɛ, and the characteristic energy-containing wave number k₀. A previous relation was limited to strong stable stratification.