Gabriela Camboim Rockett

Ground Penetrating Radar applied to the Characterization of the Itapeva Dunefield, Torres, Brazil

ABSTRACT Rockett, G.C.; Barboza, E.G., and Rosa, M.L.C.C. 2016. Ground Penetrating Radar applied to the characterization of the Itapeva Dunefield, Torres, Brazil. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 323–327. Coconut Creek (Florida), ISSN 0749-0208. Subsurface data obtained from Ground Penetrating Radar (GPR) have been used in studies in various coastal plain environments. GPR applied to dune characterization and stratigraphy is well described in the literature, and enables the distinction between different depositional patterns and their delimitation. This study aimed to characterize the stratigraphy of the Itapeva dunefield, located at the municipality of Torres, north of the Rio Grande do Sul (Brasil) coastal plain, using subsurface data. This dunefield contains aeolian forms that differ from other dunefields in Rio Grande do Sul: namely, reversing dunes. The 150 and 400 MHz frequency antennas were used to collect subsurface data in dunes located in the central portion of the dunefield, with a linked GNSS system to obtain positional data. GPR data were processed, and the geospatial data were integrated to satellite images in a geographic information system. Results show that at least two different dune packages are present in the Itapeva dunefield, indicating two different depositional phases.

Análise espaço-temporal dos ventos no extremo norte da Planície Costeira do Rio Grande do Sul, Brasil

The sediment transport between different regions is strongly influenced by wind activity, which can have great influence on the formation of coastal landscapes. Aiming to characterize the wind dynamic in the extreme north of Rio Grande do Sul (RS) Coastal Plain, historic and annual wind data (speed and direction) of four meteorological stations located in the region were analyzed in this study. Results show that in Torres station the winds that occur more often are from NE and S, and winds from W and N are rare. In the SBTR/Airport station, winds from the N-NE quadrant are the most frequent (32%), followed by the winds from SW, SSW and S. In the Central Itapeva Lake station the wind pattern changes slightly, and the most frequent wind directions are NE and SW, with more intense winds coming from SW. It was verified also a variability in the winds directions and frequency during different seasons, with more intense winds during winter. Based on the wind data from each meteorological station, it was found that in the extreme north of RS Coastal Plain the greatest winds intensity (S-SW quadrant) occur at the station which is located further south (Arroio do Sal Municipality), which is closer to the Serra Geral scarps, where the wind direction coincides with the direction free of orographic obstacles. Nevertheless, the spatial-temporal analysis showed that the different localities do not have significant differences in wind directional patterns considering the directional unit as the quadrant.