dt: $\Delta t$

Time step. Assuming $\theta>0.5$, stability is limited by

$$\Delta t < C\left[\frac{\min(D_g)}{\max(\vert U\vert)},\frac... ...TH})}, \frac{1}{2}\frac{\min(D_g)^2}{\max(\nu_{H})} \right] ,$$

where $c_i$ is the internal wave speed, $C$ is the relevant Courant number, and $D_g$ is the minimum Voronoi distance. Note that this assumes first-order upwind is used for advection of momentum. If central-differencing is used, stability is further constrained by the grid Peclet number (see Section 7.1.51 for details).