The Change of Wave Characteristics Due to Global Warming at Indonesia Seas

As an archipelago country, Indonesia’s coastal area is very vulnerable to climate change such as sea level rise, warmer ocean temperature, and increased wave height. Knowledge of wave climate change due to climate change is required for engineering purpose in various ocean and coastal activities. Then, understanding the change of wave characteristics is a major element for sustainable management in both offshore and coastal works. Unfortunately, availability and information on in-situ wave measurements are still very limited in Indonesia. Therefore, in this study, monthly variations of significant waves are studied using ERA5 database from ECMWF (European Centre for Medium-Range Weather Forecasts) from 1990 to 2020 in Indonesia Seas. A statistical analysis of wave and wind time series data has been performed to test the significance of trend during 30 years period. Mann–Kendall test is used to evaluate the trend of time series data in terms of mean value. The results show that temporal variations in wave height have an associated pattern with monsoonal wind cycle, especially for inter-island coast of the Indonesian Sea. In addition, the average of significant wave height in south Java Sea that faces the Indian Ocean shows a statistically significant increasing trend.