Statiscal analysis of significant heights of short-term seasonal series waves at the coast of Rio Grande do Norte

Abstract

This work aims to present a new approach of wave climate available for the North coast of Rio Grande do Norte, introducing spatial and temporal analyses related to a time series of the last five years. The study provides a first evaluation of the spatial distribution of significant wave heights over a temporal series between 2010 to 2015, with annual, seasonal and monthly analysis of the patterns of significant height (Hs) and average directions (DIR) throughout the spatial domain. The temporal variations are analyzed in the second step, considering the monthly averages, the seasonal variability and inter-annual variations at the coastal stations. Finally, the study offers a classification of severe wave events based on the application of the percentile technique, which percentile = P0.99 was set to establish a fixed threshold in relation to the HS values of temporal series. The annual and seasonal distribution of significant wave heights in the spatial domain shows that the zone of highest incidence, with higher values, is located at the external portion of the continental shelf, above the isobath of 25 m, with an average of 1.96 m and maximum values above 2 m for a Hs with ENE directional pattern. In seasonal analyses, during the summer months, the waves are the highest on this coast. In the seasonal and inter-annual analyses, 2010 and 2013 were considered the years of greater agitation and frequency of severe events in the region. The study corroborates for both, knowledge of the waves patterns and the possibility to assess the waves as an energy resource in this sector of the Northeastern coast.