Resumo:
The present work examines the effects of coastal upwelling on the longitudinal density
gradient within Todos os Santos Bay (BTS) and, therefore, its effect on gravitational circulation
at the entrance of the estuary, as well as the effect of gravitational circulation on
the coastal upwelling. A one-year data set of observed water temperature, mean circulation,
and river input, as well as 2 years of numerical simulation are the basis for this investigation.
The results show that the upwelling has a considerable effect on the regulation of the
thermohaline field in front of the BTS, decreasing water temperature and increasing density,
having suficient intensity to accelerate or establish the estuarine gravitational circulation.
It was also observed a frequent anticipation of increasing flow shear intensification in relation
to temperature drops, suggesting that the estuarine gravitational circulation acts as a
facilitator to the upwelling process. Furthermore, based on the results obtained with the numerical
simulations, it appears that the coastal upwelling events was also able to reestablish
an estuarine density gradient in a period when the estuarine circulation was interrupted.
