Extreme value analysis of wave climate around Farasan Islands, southern Red Sea

Abstract

The study investigates extreme value analysis of wave climate around the Farasan islands’ protected coastal zone in the southern Red Sea. It provides an overall idea of the extreme wave conditions in the southern Red Sea, which are influenced by the Indian monsoon and local climates as well as by the effect of complex topography due to the presence of corals and high steepness in the bathymetry. The significant wave height return levels for the select shallow and deep regions around the Farasan islands are estimated using extreme value models; Generalized Extreme Value (GEV) and Generalized Pareto Distribution (GPD). Both block maxima and annual maxima methods are used in the GEV and GPD established with Peak Over Threshold (POT). The GPD method gives more reliable return level estimates compared to GEV. The trend analysis shows that, the trends of near extremes (90th and 95th percentile Hs) are significant in the offshore regions around the Farasan Islands, but not significant in the nearshore regions. The seasonal analysis indicate that the seasonal estimates of extreme Hs are more reliable than annual estimates considering the differences in the seasonal wave generation mechanisms over the region.