Abstract
A discontinuous solution to a deformation-forced, semigeostrophic frontogenesis model is developed. The model atmosphere is adiabatic and has uniform potential vorticity. Surfaces of discontinuity evolve from an initial point discontinuity along a horizontal boundary and propagate into the fluid interior. The dynamical aspects of the time-dependent flow are examined and compared to observational studies and results from more sophisticated frontogenesis models. Features of interest include the development of a low-level vertical velocity jet originating at the point of intersection of the discontinuity surface with the lower boundary. The jet is associated with an intense low-level convergence on the same order of magnitude but opposite in sign to the maximum vertical component of vorticity at the surface. Other aspects of the model dynamics are also examined by considering the fields of potential temperature, alongfront wind, and Richardson number.
