Evidence for Barotropic Wave Radiation from the Gulf Stream

Abstract

Abstract Highly energetic velocity fluctuations associated with topographic Rossby waves are frequently observed over the continental slope and rise off the United States and Canadian east coast. It has been suggested that the energy source for these waves could be eastward-propagating Gulf Stream meanders, which can couple to the westward-propagating Rossby waves if the meander shape is time dependent. In this study, a historical archive of all available current meter data from the western North Atlantic has been examined for evidence of energy radiation from the Gulf Stream via barotropic/topographic Rossby waves. Maps of abyssal eddy kinetic energy (EKE) and Reynolds stress were constructed for four frequency bands (including motions with periods between 256 and 7.8 days) to examine distributions of these quantities over the largest possible geographical area. Maximum eddy kinetic energy is observed along the mean axis of the Gulf Stream at low frequencies (50–250 days), but this maximum shifts north a...