Flow Field on a Two-dimensional Wave from Orography

In a two-layer model, the wave equation is solved to obtain the resolution analytically of disturbed streamlines caused by a two-dimensional sinusoidal topography. The disturbed flow field in the upper and lower layers for varieties of temperature and wind profiles is studied. The atmospheric conditions and the topographic feature determining the amplitude of the disturbances are also discussed. The results show that the waves induced by the terrain are weaker if the lower layer of the atmosphere is deep and unstable, while the waves are stronger if the lower layer is strongly stable with a weakly stable in upper layer. The increase of the stability in the upper layer may induce untrapped waves which favour the downward transport of momentum and the formation of the strong surface wind