Spectral wave characteristics along the central coast of eastern Red Sea
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ORIGINAL PAPER
Spectral wave characteristics along the central coast of eastern Red Sea P. R. Shanas 1 & V. M. Aboobacker 1
&
Khalid M. Zubier 1 & Alaa M. A. Albarakati 1
Received: 4 October 2017 / Accepted: 9 February 2018 # Saudi Society for Geosciences 2018
Abstract The Jeddah coast lies in the central eastern Red Sea, which is characterized by the predominant northwest winds and the associated wind waves throughout the year. A detailed investigation on the spectral wave characteristics in the nearshore regions of the Jeddah coast has not been carried out yet, primarily due to the lack of data. In the present study, we have analyzed the available wave spectra measured at two nearshore locations along the Jeddah coast using wave gauges. The wave spectra were separated into wind sea and swell components using a frequency-based algorithm, and the integral wave parameters corresponding to each component were derived. Although the measurements were limited to the summer season, notable features such as the diurnal variability and the superimposition of wind seas and swells have been identified from the spectra. The superimposition is mainly due to the interaction of the young swells propagated from the northern Red Sea and the local breezes prevailing along the coast at certain periods in a diurnal cycle. Based on the wave speed calculations and the estimated time shifts between the wind and waves, the potential swell regions have been backtracked. Keywords Wave spectra . Red Sea . Jeddah coast . Diurnal variations . Sea-swell separation
Introduction Ocean wave spectra refer to the distribution of wave energy among different frequencies and directions (Portilla et al. 2009). Knowledge on wave spectra is important for engineering applications such as the design of harbors, coastal and offshore structures, and planning of marine operations (Chakrabarti 2005). The wind waves are highly irregular during their generation and growth. In the nearshore regions, complex topography transforms the wave energy, and hence modifies the spectral characteristics. In general, the shape and distribution of the wave spectra vary in time and space, which has significant implications along the coastal regions. Previous studies in the Red Sea describe the overall features of the wind waves, based on wave hindcasting, satellite observations, and available measurements (Shanas et al. 2017a; Saad 2010; Aboobacker et al. 2016; Fery et al. 2015; Gharbi 2012; Langodan et al. 2014, 2015; Ralston et al. 2013;
* V. M. Aboobacker [email protected] 1
Faculty of Marine Sciences, Department of Marine Physics, King Abdul-Aziz University, P.O. Box 80207, Jeddah 21589, Saudi Arabia
Zubier et al. 2009). However, an in-depth analysis of measured wave spectra has not yet been carried out, especially along the Jeddah coast, the central west coast of Saudi Arabia. Few studies reported the characteristics of the wave parameters along this region. For instance, Ralston et al. (2013) estimated the monthly mean significant wave heights and mean wave pe
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