Orographic effects on a 3-D barotropic lee wave across a meso-scale mountain corner

Abstract

An attempt has been made to study 3-D lee waves associated with an adiabatic, non-viscous, Bousisnesq, non-rotating, stationary dry mean flow across a mesoscale Mountain Corner hills (MCH). For simplicity, the far upstream undisturbed basic flow is assumed to have horizontal components of wind (U,V) and Brunt Vaisala frequency (N) to be independent of height. MCH is synthesized by the intersection of two semi-infinite ridges, parallel to the horizontal axes of co-ordinates. The primitive equations are used in z-coordinate. The nonlinear governing equations are linearized by using perturbation technique. The linearized equations are then subjected to two-dimensional Fourier transform. The 2nd order ordinary differential equation in the Fourier transform ŵ of perturbation vertical velocity w 0 is obtained by some algebraic simplification. This equation has been solved by using the radiational upper boundary condition and the lower boundary condition imposed by the profile of the hill at surface. The vertical velocity (w 0 ) is represented by double integral, which is very complicated. This double integral is evaluated by using asymptotic technique.