Numerical modeling of storm surges in the brazilian southeastern shelf using synopitc charts of atmospheric pressure at the surface

Abstract

A three-dimensional, linear, barotropic and meso-scale numerical model is used for the southeastern Brazilian shelf, in order to represent the composition of the main astronomical tidal constituents, superimposed to extreme meteorological effects, for specific periods of interest. However, meteorological data relative to this area are very few and sparse, so that a methodology to provide meteorological conditions to the oceanic circulation model was used, based only on atmospheric pressure charts at the surface. The pressure field was well represented, while the calculated wind speeds were much larger than the observed winds at the coast. The model results indicate that it is possible to associate the predominant high pressure center in the South Atlantic and the correspondent surface elevations parallel to the coastline to an approximately geostrophic oceanic circulation system. On the other hand, the passage of cold fronts in the area induces transient systems that modify the geostrophic pattern, also changing the surface elevation isolines configuration.