Deformation of Barotropic Inertia-Gravity Waves by a Uniform Geostrophic Current

Abstract

The effect of a uniform geostrophic current on barotropic inertia-gravity waves in a shallow-water channel model is studied. Numerically obtained normal modes are compared with analytical results for Kelvin, Poincar and trapped waves. In general, the results show that an increasing current strength complicatedly changes the intrinsic frequency of the waves and dramatically alters their structure from that of channel waves to that of trapped waves. Implications for geostrophic adjustment and normal mode initialization are briefly examined.