title: Sea level anomaly on the Patagonian continental shelf: Trends, annual patterns and geostrophic flows.
abstract: We study the annual patterns and linear trend of satellite sea level anomaly (SLA) over the southwest South Atlantic continental shelf (SWACS) between 54ºS and 36ºS. Results show that south of 42°S the thermal steric effect explains nearly 100% of the annual amplitude of the SLA, while north of 42°S it explains less than 60%. This difference is due to the halosteric contribution. The annual wind variability plays a minor role over the whole continental shelf. The temporal linear trend in SLA ranges between 1 and 5 mm/yr (95% confidence level). The largest linear trends are found north of 39°S, at 42°S and at 50°S. We propose that in the northern region the large positive linear trends are associated with local changes in the density field caused by advective effects in response to a southward displacement of the South Atlantic High. The causes of the relative large SLA trends in two southern coastal regions are discussed as a function meridional wind stress and river discharge. Finally, we combined the annual cycle of SLA with the mean dynamic topography to estimate the absolute geostrophic velocities. This approach provides the first comprehensive description of the seasonal component of SWACS circulation based on satellite observations. The general circulation of the SWACS is northeastward with stronger/weaker geostrophic currents in austral summer/winter. At all latitudes, geostrophic velocities are larger (up to 20 cm/s) close to the shelf-break and decrease toward the coast. This spatio-temporal pattern is more intense north of 45°S.
authors.affiliation: Departamento de Ciencias de la Atmósfera y los Océanos Universidad de Buenos Aires Buenos Aires Argentina; Centro de Investigación del Mar y la Atmósfera Buenos Aires Argentina; Instituto Franco Argentino para el estudio del clima y sus impactos (UMI-IFAECI), Argentina; Now at International Pacific Research Center School of Ocean and Earth Science and Technology University of Hawaii at Manoa Honolulu Hawaii.
authors.forename: L A
authors.initials: LA
authors.lastname: Ruiz Etcheverry
authors.affiliation: Departamento de Ciencias de la Atmósfera y los Océanos Universidad de Buenos Aires Buenos Aires Argentina; Centro de Investigación del Mar y la Atmósfera Buenos Aires Argentina; Instituto Franco Argentino para el estudio del clima y sus impactos (UMI-IFAECI), Argentina.
authors.forename: M
authors.initials: M
authors.lastname: Saraceno
authors.affiliation: Departamento de Ciencias de la Atmósfera y los Océanos Universidad de Buenos Aires Buenos Aires Argentina; Instituto Franco Argentino para el estudio del clima y sus impactos (UMI-IFAECI), Argentina; Departamento Oceanografía, Servicio de Hidrografía Naval Buenos Aires Argentina.
authors.forename: A R
authors.initials: AR
authors.lastname: Piola
authors.affiliation: College of Earth, Ocean and Atmospheric Sciences Oregon State University Corvallis Oregon USA.
authors.forename: P T
authors.initials: PT
authors.lastname: Strub
keywords: annual cycle; continental shelf; sea level anomaly