Variability of currents on the inner shelf of Tramandaí, RS during the summer of 2014

Abstract

Upwelling and Downwelling events in very shallow water still are poorly understood on brazilian coastal. This work aims to obtain a better understanding of ocean circulation in shallow waters, such as coastal currents and sea level oscillations. An acoustic waves and currents profiler, AWAC, Nortek brand, was anchored at 11 m depth off Tramandaí beach, which was programmed to record a continuous series of waves and currents data, beginning on December 17, 2013 and ending on March 13, 2014 (summer). The results indicated that in the inner shelf the direction of the currents for short periods reverses, sometimes Southward, sometimes Northward. Also, it was observed the maximum velocities of 0.6 and 0.9 m.s-1 on the bottom and on the surface, respectively. In addition, a flow rate of 0.018 m.s-1 to S was calculated based on the average profile of the water column. Furthermore, were found indicative of upwelling and downwelling circulation patterns, from wind and current direction analysis as well, variations in water temperature and also in average sea level.