Abstract
The semigeostrophic Eady problem is used as a testbed for frontogenetical calculations using a specific numerical model. Over 3 days of integration, the numerical solutions agree very well with their analytical counterparts. The increasing deviations in the vertical field of motion during the last day before the analytical model breaks down are attributed to the inability of a grid-point model to handle evergrowing contrasts correctly. The dependence of the time-scales on the external parameters is addressed.