CoAuthors

Martin Saraceno (Centro de Investigaciones del Mar y la Atmósfera (CIMA) CONICET/UBA, Argentina); Patricia Martos (INIDEP, Argentina); Raul Guerrero (INIDEP, Argentina); Alberto Piola (Departamento de Oceanografía, Servicio de Hidrografía Naval (SHN), Argentina); Christine Provost (Laboratoire d’Océanographie et du Climat: Experimentation et Approches Numériques, France); Guillermina Paniagua (Centro de Investigaciones del Mar y la Atmósfera (CIMA) CONICET/UBA, Argentina); Ramiro Ferrari (Centro de Investigaciones del Mar y la Atmósfera (CIMA) CONICET/UBA, Argentina); Camila Artana (Laboratoire d’Océanographie et du Climat: Experimentation et Approches Numériques, France)

With the aim of analyzing the performance of satellite altimetry surface currents we compared four ocean currents time series collected by upward-looking ADCPs deployed within the French-Argentine CASSIS project (http://www.cima.fcen.uba.ar/malvinascurrent/es/) over the Patagonian Continental Shelf (PCS) to different satellite products. Results show low correlation coefficients (vector correlations lower than 0.3) and a root mean square differences (RMSD) of ~6 cm/s. We associate the low correlation to the fact that in situ currents are mostly ageostrophic. Indeed, this region is highly affected by winds. The best representation of surface currents was accomplished by a regional product developed by CLS that includes an estimation of the Ekman component. We also found that the difference between satellite and in situ currents was larger during specific events associated to the passage of synoptic storms near the PCS. Nevertheless, we did find excellent agreement between in situ sea surface height (SSH) and satellite total water level (TWL, = altitude – range) computed from 20Hz Jason 2 data (correlation coefficients exceed 0.9 and RMSD is ~10 cm). By adding each satellite correction one by one to the TWL, we found that high-frequency atmospheric fluctuations and ocean tides need to be improved to accomplish a better representation of SSH and, consequently, of surface geostrophic currents.
The wide Patagonian Continental Shelf (PCS) is one of the most biologically productive areas of the world ocean. It harbors the spawning and nurturing area of several fish species of economic relevance. In order to better understand biological processes, it is important to characterize the spatio-temporal variability of the main physical variables. In this sense, satellite altimetry data will be very useful once validated.