Steepness of surface gravity waves measured in the eastern Arabian Sea during peak monsoon months

Abstract

Information on wave steepness is required to design marine facilities and plan safe maritime navigation. In this work, the steepness of the individual waves measured in the coastal waters at five locations using wave rider buoys during the peak monsoon months (June and July) are examined along the west coast of India, covering a distance of ∼950 km. A nearly constant value of ∼0.025 for average wave steepness is observed for all locations except the southern location (∼0.018). At different locations, the maximum wave height ranged from 5.40 to 8.33 m, and the steepness of the largest waves varied from 0.047 to 0.082 and is much smaller than that for the wave-breaking limit. The steepness of the highest waves is larger than its average during the peak monsoon months. The mean wave height during June–July shows less spatial variation over ∼325 km except at the south-eastern Arabian Sea, and the mean wave period is approximately the same at all locations. Significant wave steepness based mean wave period compares well with the average of the steepness of waves measured during the 30-min period. Interannual variations in the average steepness in June–July during ten years are up to 9.1%.