Changing wind-generated waves in the Red Sea during 64 years

Abstract

This study analyzes the wind-generated wave climate conditions in the Red Sea. A 64-year (1959?2022) wave hindcast is developed using the spectral wave model WAVEWATCH III forced with ERA5 wind fields. The study addresses the climatologies of the significant wave height (Hs), mean period (Tm), and wave power (P) parameters, as well as the wind-sea and swell distributions throughout the basin. Special interest has been paid on assessing the extreme climate conditions. Additionally, the climate variability at seasonal and inter-annual scales, and the long-term trends are analyzed. The relationship between the Red Sea wave climate and the large-scale teleconnection climate patterns is investigated. The model is calibrated for wind-wave growth and validated against buoy and altimeter measurements revealing higher performance than previous datasets. The root mean square errors of Hs and Tm are reduced by 25% and 37%, respectively. Results show that wind-seas dominate in the northern and southernmost Red Sea regions. We also detect that the 100-year return period of Hs reaches ~5 m in the central basin. Furthermore, regional annual and seasonal variations of the wave climate show strong correlations with the circulation patterns described by the North Atlantic Oscillation at the northern Red Sea and both the Dipole Mode Index and El-Niño Southern Oscillation at the southern Red Sea. Finally, contrasting behaviours of negative and positive trends occur at the southern and northern regions, respectively, for Hs, and P with a contrary behavior for Tm. Trends under both mean and extreme conditions are mild, reaching 3 cm/ decade, 0.016 s/decade, and 0.3 kW/m/decade for Hs, Tm, and P, respectively, in the northern basin in winter.