Deep-water wave spectral characteristics in East-Central Arabian Sea

• Published in: Arabian journal of geosciences 2022-03, Vol.15 (6), Article 507
• Main Authors: Ramasamy, Keerthivasan, Ganesan, Latha, Ramasubbu, Balamurugan, Ramasamy, Venkatesan
• Format: Article
• Language: English
• Subjects: Annual variations; Buoys; Coastal waters; Deep water; Deep-water waves; Earth and Environmental Science; Earth science; Earth Sciences; Hurricanes; Mathematical models; Monsoons; Original Paper; Parameters; Peak frequency; Significant wave height; Spectra; Swell; Tropical climate; Tropical cyclones; Water waves; Wave data; Wave direction; Wave height; Wave parameters; Wave period; Wave spectra; Wind
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-022-09711-1

This paper presents the work carried out on the analysis of spectral characteristics of deep-water waves in the East-Central Arabian Sea using time series measurements from the moored buoy. The intra-annual variations in the spectra during the pre-monsoon, monsoon and post monsoon seasons, and inter-annual variations over eight years from 2012 to 2019 have been studied using in situ data in the Arabian Sea. Though a few studies on wave spectral characteristics in the Arabian Sea have been reported in the literature, they mainly focussed on coastal waters or model outputs. A detailed investigation using measured in situ data in the deep waters of the Arabian Sea has not been carried out due to lack of measurements. The main objective of this paper is to study wave spectral characteristics using in situ measured wave data over a long period in the deep waters of the East-Central Arabian Sea. Further, the comparison of model-derived wave parameters with measured data has been carried out to check the model performance. The study shows that the wave spectra are double-peaked in January–February and are wind dominated. From March onwards, swell influence begins, and the wind sea component decreases. The spectra are single-peaked and swell dominated in the Southwest monsoon period (June–September). During June to August, peak frequencies are distributed around 0.06 to 0.1 Hz with single-peaked spectra. Swell dominated double-peaked spectra are observed from October to December. Significant wave height (H m0 ) up to 8.89 m and a maximum wave height (H max ) of 12.54 m were observed during Tropical Cyclone Ockhi in 2017. ERA5 (ECMWF Reanalysis 5) data were compared with the measured wave parameters such as significant wave height, wave period and mean wave direction and found to be good, but the model underestimates the wave parameters by about 31% during extreme events. This study illustrates the usefulness of having a long measurement period with which model performance can be improved.