Study of the meteorological tide in the Río de la Plata

Abstract

The meteorological tide generation and the characteristics of its propagation into the Río de la Plata are examined in this paper. Meteorological tide refers to departures of the sea surface elevation from the predicted astronomical tide during days to a few weeks and is generated by atmospheric forcings. The study was carried out analyzing hydrographic records and also using a hydrodynamic numerical model. The numerical model was implemented both in a regional domain and in a local domain focused in the Río de la Plata. The numerical model allowed us to understand the generation of the events and the relative importance of the remote and local forcings. Based on hydrographic records of the Río de la Plata and NCEP–NCAR reanalysis data, the synoptic conditions leading to the most significant meteorological tide events were identified. Using simultaneous hydrographic records at various stations in the Río de la Plata, we analyzed the propagation time of the events between stations and the amplitudes changes. The results show that the main meteorological tide events are generated in the Argentinean continental shelf and then propagate northward as coastal trapped waves until they reach the estuary. For the largest events in the studied data series a good relationship between the amplification in their amplitudes and the local wind conditions was found.