Quasi-Geostrophic versus Non-Geostrophic Frontogenesis

Abstract

This study examines frontogenesis which is forced by a nondivergent horizontal wind field which contains stretching deformation. The initial conditions are formulated in such a way that the departures from the basic wind field are independent of x. The linear and nonlinear hydrostatic primitive equations are solved numerically and the solutions are compared. The linear solutions are very close to the solutions of the quasi-geostrophic equations. The latter equations predict fronts which have some unrealistic features and these equations predict discontinuities only for very large time. The nonlinear solutions are much more realistic than the linear solutions and they imply the formation of discontinuities within a finite period of time.