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Global average wave height map.  

Global average wave height map.  

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Article
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The aim of this paper is to report on a possible correlation between the Lévy index for wind velocity and the mean Energy Density of sea surface waves in the same location. The result is based on data obtained from 6 buoys located around the coast of Ireland and maintained by the Marine Institute of Ireland and a further 144 buoys located at variou...

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Context 1
... energy and power densities of a wave are proportional to the square of the wave amplitude and knowledge of the average wave height is therefore important when considering where to place a wave farm. Figure 2 shows an average wave height map of the world where it is clear that the northern hemisphere (i.e. the northern Atlantic and Pacifc oceans) have the largest average wave heights. Further, in terms of the propensity of these waves to coast lines, there are two principal regions that stand out: (i) the Aleutian Islands; (ii) the west coasts of Ireland and Scotland. ...
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... this does not effect the statistical characteristics of the data, and, in each case, the data is seen to be Rayleigh-type distributed as illustrated in Figure 19 which shows 100-bin histograms of the signals given in Figure 18. Figure 20 shows plots of the Energy Density, the Power Density and the Energy Flux computed from equations (1), (2) and (3), respectively, using the samples of data from the M1 buoy shown in Figure 18. Note that all three signals have similar time signatures, and, apart from scaling, their statistical characteristics are similar. ...
Context 3
... of the goodness-of-fit associated with probability plots show that the data conform best to a Rayleigh distribution (compared with the normal, lognormal, exponential, extreme value and the Weibull family of distributions). This is demonstrated in Figure 22 which shows that both the energy density and Lévy index appear to be Rayleigh distributed accept at the extrema. Interestingly, the Lévy index is better Rayleigh distributed than the energy density. ...
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... Rayleigh distributed characteristics of the energy density is to be expected as it maps to the distribution of wave heights which, for a linear wave model, are Rayleigh distributed (see Figure 19). The deviation of data points from this distribution (as shown in Figure 22) is a possible reflection of non-linearities which are known to occur from time to time in sea surface waves especially with regard to deep water ocean waves and can lead to the generation of 'Freak Waves' (see [28] and references therein). However, application of the Wilcoxen Signed Rank Test (which removes information on the shape of the distribution given that Ranks are resistant to outliers) yields a 'p-value' of 1.1442 × 10 −21 and validity of the Null Hypothesis in this case (i.e. that the population medians are equal or the difference in population medians is zero) can be taken to be false. ...
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... although the energy density and Lévy index appear to conform to the same distributions, they are from 'different populations' and therefore independent. This is reflected in the scatter-plot given in Figure 23 which shows no clear correlation between parameters plotted. Thus, in the following section, we consider a new relationship between these parameters which is based on an analysis of the linear wave model compounded in equation (4) and (6). ...
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... c and m are arbitrary (real) constants. Figure 24 shows a plot of the data (samples of which are given in Tables I and II) and a linear fit to the data based on equation (9) where (working to 4 decimal places) m = −0.42699 and c = 1.0236 (the norm of residuals being 3.5562). ...
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... CONCLUSIONS AND FUTURE WORK The results given in Figure 23 are an indication of the possible validity of the scaling given by equation (9). The results provide the potential for developing a computational procedure to predict the mean Energy Density of a sea surface from data obtained on the wind velocity alone. ...
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... the EWEA vision becomes a realisation, the added concentration of HVDC terminals, offshore wind farms and increased grid interconnection will help drive forward the competitiveness of wave energy as they will be able to exploit the infras- tructure of wind farms in what are otherwise no-go marine areas. (Figure 25). We conclude this paper with the following points: ...

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