Indian Ocean Rossby waves observed in TOPEX/POSEIDON altimeter data and inmodel simulations

Analysis of 3 years of TOPEX/POSEIDON (T/P) altimeter data in the Indian Oc ean revealed discrepancies between observed and theoretical Rossby wave pha se speeds. Rossby waves were observed at all latitudes using Hovmoller diag rams or longitude/time plots; their phase speeds were computed using two-di mensional Fast Fourier Transforms (FFTs). Complex Principal Component Analy sis (CPCA) was applied to detect travelling waves. A simple wind-driven lay er model was implemented for this region and forced with the ERS-1 scattero meter winds, sampled over the same period as the T/P data, to demonstrate t hat these winds account for much of the observed Rossby wave activity.