GULF STREAM-GENERATED TOPOGRAPHIC ROSSBY WAVES

An inverse ray tracing model is applied to observations of 40-day topo graphic Rossby waves on the continental slope off of Cape Hatteras, No rth Carolina, to determine their origin. The rays are traced seaward a nd extend into the deep Gulf Stream, where the bottom slope remains st rong enough that topographic beta dominates planetary beta. This enabl es coupling to occur between eastward propagating Gulf Stream meanders and topographic waves with eastward phase speed and matching zonal wa velength. Previous satellite observations indicate that the most frequ ently occurring Gulf Stream meanders have a period of 40 days, and the model reveals that, as these meanders pass a topographic bend near 71 degrees-72 degrees W, they are able to couple to the observed topogra phic waves traced back from Cape Hatteras. The 40-day Gulf Stream mean ders occur in bursts, which leads to associated bursts of the topograp hic waves.