Ageostrophic (two-dimensional) flow of a rotating stratified fluid orographically perturbed

We consider the perturbation of a stratified rotating fluid due to the crossing of a mountain ridge. The behaviour of the solutions is examined in the primitive Navier-Stokes equations in linear form studied by Queney. We produce the Green's functions of the problem at ground level at any distance from the perturbing ridge; in this sense it is an extension of the theory presented by Pierrehumbert. Furthermore, we discuss the relative contribution of the different terms and we examine the behaviour of small-scale waves with altitude. This work is also relevant for the parametrization of the subgrid physical effect in large numerical models, like the barrier effect of the Alps or the Rocky Mountains.