3f- 



o - Norrow Spectrum 

 • - Brood Spectrum 



T 2 



1.0 1.5 2.0 



Observed Hgf. (m) 



Figure 3. Comparison of observed and predicted wave heights at the 



nearshore gage (Waverider gage 610), Duck, North Carolina. 



Table 2. Average deviation of Bretschneider and 



Reid's theory from observed wave heights. 



Wave spectra 



Deviation 

 (pet) 



Regression line 



Narrow 



+4.2 



y = 0.83x + 0.33 



Broad 



-15.3 



y = 0.87x - 0.05 



All spectra 



-6.5 



y = 0.91x + 0.03 



(multipeaked) 







^Correlation coefficient for all spectra equals 

 0.926. 



Table 3. Illustration of the inapplicability of Bretschneider and 

 Reid's theory in areas of irregular bottom topography. 



Date 



Time 



Wave height (m) 



Deviation 

 from observed 

 (pet) 



Estimated H^^^j 

 by including 

 refraction 

 (m) - 



Observed 



Predicted 



"s625 "s665 



"s665 



13 Sept. 



1978 



0300 



0.9 



0.5 



0.96 



91.2 



0.50 



13 Sept. 



1978 



2100 



2.5 



1.6 



2.33 



■ 45.8 



1.50 



13 Sept. 



1978 



2300 



2.4 



1.4 



2.24 



60.3 



1.44 



14 Sept. 



1978 



1100 



2.1 



1.3 



1.97 



51.2 



1.26 



15 Sept. 



1978 



1600 



1.3 



0.7 



1.29 



85.1 



0.78 



18 Oct. 



1978 



0700 



2.2 



1.6 



2.5 



55.1 



1.32 



18 Oct. 



1978 



J100_ 



2.1 



1.4 



2^2 



59.1 



1.26 



12 



