THE RÍO DE LA PLATA ESTUARY HYDROLOGY AND CIRCULATION
Diego Moreira y Claudia Simionato
Departamento de Ciencias de la Atmósfera y los Océanos (DCAO, FCEN-UBA), Centro de
Investigaciones del Mar y la Atmósfera (CIMA, CONICET-UBA) and Instituto Franco-Argentino
para el Estudio del Clima y sus Impactos (UMI IFAECI, CNRS-CONICET-UBA). Ciudad
Universitaria Pabellón II Piso 2 (C1428EHA) Ciudad Autónoma de Buenos Aires, Argentina.
Manuscript received on 29th August 2017, in final form on 1st December 2017
This work compiles and summarizes the current knowledge of the Río de la Plata Estuary hydrology and circulation, reviewing the existing literature on the issue.
We firstly describe the main forcings of the circulation in the estuary -its geometry and bathymetry, runoff, wind-waves, tides and winds- emphasizing, when it applies, in their temporal scales of variability from intra to inter-annual. Then, we discuss the density structure and the main circulation patterns, synthesizing results derived from modelling and observational studies. The description of the circulation is done in two parts: (i) firstly reporting the barotropic (vertically averaged) motion, which strongly affects the net mass transport and sea surface height variability in the estuary and, therefore, is linked to the surges; and (ii) secondly, discussing what it is known about the baroclinic (vertically varying) currents in the frontal zone and their influence on the density structure. Finally, the paths of the freshwater masses of the main tributaries along the estuary are described and the mechanisms that favour retention in the frontal zone are discussed.