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Ocean Science An interactive open-access journal of the European Geosciences Union
Ocean Sci., 13, 365-378, 2017
https://doi.org/10.5194/os-13-365-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Technical note
03 May 2017
Wave spectral shapes in the coastal waters based on measured data off Karwar on the western coast of India
M. Anjali Nair and V. Sanil Kumar Ocean Engineering Division, Council of Scientific & Industrial Research-National Institute of Oceanography, Dona Paula, 403 004 Goa, India
Abstract. An understanding of the wave spectral shapes is of primary importance for the design of marine facilities. In this paper, the wave spectra collected from January 2011 to December 2015 in the coastal waters of the eastern Arabian Sea using the moored directional waverider buoy are examined to determine the temporal variations in the wave spectral shape. Over an annual cycle for 31.15 % of the time, the peak frequency is between 0.08 and 0.10 Hz; the significant wave height is also relatively high (∼ 1.55 m) for waves in this class. The slope of the high-frequency tail of the monthly average wave spectra is high during the Indian summer monsoon period (June–September) compared to other months, and it increases with an increase in significant wave height. There is not much interannual variation in the slope for swell-dominated spectra during the monsoon, while in the non-monsoon period when wind-seas have a high level of influence, the slope varies significantly. Since the exponent of the high-frequency part of the wave spectrum is within the range of −4 to −3 during the monsoon period, the Donelan spectrum shows a better fit for the high-frequency part of the wave spectra in monsoon months compared to other months.

Citation: Nair, M. A. and Kumar, V. S.: Wave spectral shapes in the coastal waters based on measured data off Karwar on the western coast of India, Ocean Sci., 13, 365-378, https://doi.org/10.5194/os-13-365-2017, 2017.
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Short summary
The information on wave spectral shapes that is required for designing marine structures is presented based on wave data collected from January 2011 to December 2015 in the coastal waters of the eastern Arabian Sea. The variations in the high-frequency tail of the wave spectrum in different months are presented. The slope of the high-frequency tail of the monthly average wave spectra is high during the Indian summer monsoon period (June–September) compared to other months.
The information on wave spectral shapes that is required for designing marine structures is...
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