Influence of mid‐ocean ridges on Rossby waves

Abstract

Influence of mid‐ocean ridges on Rossby wave activity is discussed in simple models. Ridges can influence Rossby waves in two ways, topographic scattering and mid‐ocean local generation. It is found that both processes are rather sensitive to model parameters such as frequency, ridge height, and ridge width in both barotropic and baroclinic models. In the barotropic model, for certain model parameters there is perfect transmission of Rossby waves, while for some other model parameters the transmission is rather weak. In a two‐layer model, if the frequency is not low enough, trapping of baroclinic signals around topography will occur. The mid‐ocean ridge is generally not as efficient as the eastern boundary in generating barotropic waves except at high frequencies in a barotropic model. It is much more efficient than the eastern boundary in generating baroclinic waves when wind forcing has a very large zonal scale, while less efficient when wind forcing has a short zonal scale.