A parameterization of two-dimensional transport is developed for application to photochemical models of stratospheric trace species. It is shown that in a first approximation tracer transport in the meridional plane may be treated as an advective, rather than a diffusive, process. The mean meridional motion used in this advective model is a modified Eulerian mean which is a good approximation to the Lagrangian mean motion. The potential of the proposed parameterization is demonstrated by a simple numerical experiment in which the equilibrium distribution is computed for a tracer with a uniform tropospheric source and a stratospheric sink proportional to the local mixing ratio. The resulting distribution is qualitatively in accord with the observed stratospheric distribution of trace species whose sources are in the troposphere, e.g., N2O.