Analysis of extreme wave probabilistic return value based on the 20-year spectral and empirical wave modeling approach in the Coastal Area of Pangandaran

Abstract

Abstract The coastal area of Pangandaran is located on the southern coast of Java Island, Indonesia. It offers stunning beach panoramas, and tempting waves for surfers, while also providing livelihoods for people who depend on the marine biodiversity and abundance of fish caught in the surrounding waters. However, its exposure to the Indian Ocean makes it susceptible to extreme waves, posing risks to tourism, fishing, and safety. This study aims to conduct an extreme wave hazard analysis based on the Probabilistic Return Value (PRV) using Significant Wave Height (SWH) data for over 20 years of data to obtain a wave climate value in the Batukaras area. The SWH values are obtained from two methods, numerical spectral wave modeling using Simulating Waves Nearshore (SWAN) and calculations using an empirical formula from the Joint North Sea Wave Project (JONSWAP), both using wind data from the ERA-5 Satellite. Based on these calculations, the Gumbel distribution was analysed to determine the PRV value on the coast. By estimating the return value of extreme waves based on the spectral SWAN method, for a return period of 300 years, extreme wave events occur at a height of 2.01 m to 2.64 m at a depth of 5-21 m. Meanwhile, the empirical JONSWAP method generates the same probability for wave heights of 7.19 m to 12.81 m based on statistical predictions based on modeling data. Based on these results, community and tourist preparedness on the coast of Batukaras Village is expected to increase, particularly during bad weather.