kappa_sH: $\kappa_{sH}\ge 0$

Laminar horizontal diffusivity of salt in units of m$^2$ s$^{-1}$. For stability

$$\frac{\kappa_{sH}\Delta t}{\mbox{min}(D_g^2)}<\frac{1}{2} ,$$

where $D_g$ is the distance between Voronoi points.