FORECAST STRUCTURE DEVELOPMENT FOR MODELLING THE SOUTHERN BRAZILIAN CONTINENTAL SHELF HYDRODYNAMIC

Global forecast models have been widely used worldwide; however, they lack ability to prescribe high quality local data. In this paper, an assembly of oceanographic (RTOFS) and atmospheric (GFS) global data base are used to set up a nested forecast system. The approach proposed relies on the  sage of python and FORTRAN scripts to download and assemble global metocean data, in addition to interpolate it towards the study area numerical grid as boundary conditions. Therefore, the TELEMAC-3D hydrodynamic model is automatically initiated in order to provide the regional forecast for the Southern Brazilian Continental Shelf. Results shows that the methodology proposed represent properly the flow dynamics inside the Patos Lagoon and also in the Tramandaí beach, with low/high frequency dynamic effects and influences being reported

ESTIMATING SURFACE VELOCITIES IN THE SOUTHERN BRAZILIAN AND URUGUAYAN CONTINENTAL SHELVES USING THE MAXIMUM CROSS-CORRELATION METHOD

The present study investigates the viability of using the maximum cross- correlation method on ocean color imagery to estimate surface velocities on the Southern Brazilian and Uruguayan continental shelf. The method searches for maximum correlation areas in two sequential images, determining the displacement of oceanographic features within the time interval of the images acquisition. We use the NWL550 parameter of MODIS-Aqua imagery, once it is well correlated with the total suspended matter in the water and provides relatively well-defined optical features on the Southern Brazilian and Uruguayan continental shelves. The estimated velocity fields showed a preferential direction northward, with average intensities between 0.06 m/s and 0.11 m/s. The frequent cloud coverage and the diffusive processes restrict the number of image pairs suitable for the analysis. Nevertheless, the method showed potential for investigating the current velocity fields on the study area, as the estimates are in agreement with the wind fields and the velocities' intensities are well within the values previously described in the literature for the region

TEMPORAL VARIABILITY OF LONGITUDINAL SEDIMENT TRANSPORT ON THE BRAZILIAN CONTINENTAL SHELF

The sediment transported along the coast can alter the existing balance in certain environments, causing or accelerating erosive processes, and resulting in economic and environmental damages. In this way, predicting changes in the coastal zone and understanding the beach processes is an essential source of information for the elaboration of coastal management plans. In this context, the present work aims to estimate the alongshore sediment transport (LST) in several sectors of the Brazilian Coast, identifying the annual average and the predominant transport. This study was conducted for the period between the years 1979 and 2015, using computational modeling to investigate the behavior of the waves, and empirical formulas to calculate the LST rates. In addition, the temporal variability was investigated through the wavelet analysis. The results showed a great diversity in the wave climate behavior along the Brazilian Coast, presenting a good correlation in terms of magnitude between the estimation of LST and past studies in the different sectors analyzed. The place where transport has become pronounced understands the sector between Alagoas and Rio Grande do Norte states, while the opposite was observed in the Southern part of Bahia. The wavelet analysis showed that the spectrum of LST time series has a significant amount of energy for processes with a seasonal and annual variability, indicating that the northern regions of Brazil are most affected by the interannual processes. In this sense, informations along the Brazilian coast are presented, that may be considered in future projects, involving the sustainable management of the coastal zones

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