Typical scenarios of wave regimes off Rio Grande do Sul, Southern Brazil

Abstract

In this study, 30 years of sea state data, reconstructed by the wave generation model WWIII for the oceanic area, were used to investigate wave regimes in southern Brazil. By applying a splitting routine to the spectra generated by WaveWatch III (WWIII), each sea state was decomposed into its primary and secondary wave systems. Histograms of the wave height and period against the direction of incidence, constructed for the 30-year period, showed that the region possesses two major wave systems: seas from the E quadrant, and swells from the S quadrant. In a more detailed characterization, histograms constructed with 30 years of data were compared with annual histograms. and the results were used to identify the year that best represented the totality of the data. For the representative year identified, clusters analysis was applied, and six typical scenarios were found for the wave system off Rio Grande do Sul, southern Brazil: (1) E swells, (2) E seas, (3) W seas, (4) S seas, (5) S swells, and (6) SE ground swells. A seasonal analysis revealed that S swells are dominant in the autumn and winter, whereas E quadrant waves (ENE swells and ENE seas) predominate in summer and spring, with more swells in spring and more seas in summer.