Contribuição atmosférica no nível residual da Ilha da Trindade, Brasil

Abstract

Tides are periodic movements of water masses originated from the attraction force between the Sun, Moon and Earth and the centrifugal force of the Earth-Moon system. The regular tidal amplitudes in the oceans are constantly modifying. These changes can be intensity or mildly, depending on the meteorological and oceanographic processes that are acting. In this study data from sea level, atmospheric pressure, and wind (zonal and meridional components), collected from a weather and tide station installed on the Ilha da Trindade (IT), were used. It is the first time that this type of study is carried out at this location. Tidal harmonic analysis was performed to characterize the tidal regime at this location based on the harmonic tidal constituents and to acquire the residual series. The influence degree of these parameters, in the sea level, was analyzed by using spectral and cross correlations analysis between the time series, applying, in same cases, the cosine Lanczos filter. The best correlation obtained between the atmospheric pressure and residual was -0.23(r²=5%) with cut off frequency of 24 hours. Considering the wind time series the best correlation was that between cross-shore wind and residual, with -0.40 (r²=17). In this case it was applied a filter with cut off frequency of 36 hours.