Low Frequency Variability in the Southeastern Pacific
Andres Vega, Yves duPenhoat, Boris Dewitte, Oscar Pizarro, Rodrigo Abarca del Rio
We study the propagation and forcing of baroclinic Rossby waves in the eastern South Pacific Ocean from TOPEX/POSEIDON and ERS-1/2 altimetric data (TP/ERS). A quasi-geostrophic lineal model is used to evaluate both wind and coastal forcing in that region. Preliminary results show long Rossby wave propagating from the South American coast to the interior of the ocean. At annual period, these waves are generated at the coastal boundary by the annual fluctuation of the alongshore wind stress. At interannual periods most of the variability along the coast is of equatorial origin. These coastal oscillation generate interannual Rossby waves that propagate the coastal signal, and so the ENSO variability, to the interior of the South Pacific Ocean.