Variations in short-term statistics of waves observed in the coastal waters of the eastern Arabian Sea

Abstract

Understanding the short-term statistics of waves is crucial for various marine applications. Present study investigates variations in the short-term statistics of waves in the eastern Arabian Sea, at a water depth of 15 m utilizing 172,704 30-min-long sea state records from 2010 to 2020. The maximum recorded individual wave height during the study period is 8.3 m. Individual wave period, height, length and steepness are higher during the monsoon (June–August). Consequently, the number of waves is lower than it is in the non-monsoon. Moreover, there are high energy swells during high wave events, and during the non-monsoon, the wave spectrum is multi-peaked, with low-frequency swells and high-frequency wind-seas. The crest height of the largest wave in different years during the study period is 0.57–0.60 times the wave height. The characteristic wave height, H1/10, is 1.24 times the significant wave height, and the maximum wave height is 1.6 times the significant wave height. Significant inter-annual variability exists in the exceedance probabilities of waves with higher heights. For the extreme sea state, the probability of the exceedance of normalized wave heights is in good agreement with the Rayleigh, Forristall and Van Vledder distributions. However, the crest heights only follow the Rayleigh distribution.