Diapycnal eddy diffusivity

Short definition of Diapycnal eddy diffusivity (Diapycnal eddy diffusivity $K_{\rho }$)
Diapycnal eddy diffusivity (for buoyancy) is defined from the buoyancy flux $\overline{w^{\prime }{\rho }^{\prime }}$ and the background density gradient $\frac{\partial \rho }{\partial z}$

This is the common definition for Diapycnal eddy diffusivity, but other definitions maybe discussed within the wiki.

Osborn 1980 showed that the buoyancy eddy diffusivity $K_{\rho }=\frac{\overline{w^{\prime }{\rho }^{\prime }}}{\partial \rho /\partial z}$ could be reduced to $K_{\rho }=\mathrm{\Gamma }ϵN^{-2}$ via the "mixing efficiency" $\mathrm{\Gamma }$ and the background stratification $N=\sqrt{\frac{-g}{{\rho }_O}\frac{\partial \rho }{\partial z}}$