Resumen de Eddy characteristics and tracer transports from TP/ERS altimetry, in a region offshore Chile

Alexis Chaigneau, Oscar Pizarro

• Based on 9 years (1993-2001) of Sea Level Anomaly measurements from TP/ERS altimeters, we characterize the mesoscale structures of the eastern South Pacific (10-35°S, 70-100°W). Integral zonal, meridional, and temporal scales of the mesoscale activity are described geographically in the study region. The length scales increase toward the north in agreement with the increase of the Rossby radius, whereas timescales show higher values in the south of the domain. Typical values of (Lx, Ly) are around 50 km at 35°S and 80-90 km at 10°S with elongation in the zonal direction revealing the anisotropic nature of the mesoscale structures. Timescales are in the range 15-45 days. We also estimate a space-varying eddy transfer coefficient K which parameterize the effect of the eddies on the lateral tracer transports. K increases in the regions of high levels of eddy kinetic energy and is in the range of 110(7) to 410(7) cm².s-1. Considering mean climatological property gradients, we show that near the coast, the mesoscale eddies can play an important role on the long term heat and salt budgets