The remaining hypotheses (a, b, c, and f) pertain to the frequency con- 

 stituents in each field record. The first of two approaches to estimating the 

 constituents was an FFT analysis to produce a band spectrum with 0.011-hertz 

 bandwidth. This procedure is typical of routine field data analysis proce- 

 dures in use. The second approach was MRS analysis to identify prominent 

 constituents to an accurancy of about 0.0002 hertz. Contrary to FFT analysis, 

 the MRS analysis provides a meaningful phase as well as amplitude for each 

 constituent. A visual comparison of field data time series with time series 

 synthesized from MRS constituents (App. B) indicates that prominent wave 

 grouping characteristics of the field record are also present in the synthe- 

 sized record. 



Figures 16 to 29 indicate how wave grouping is represented in the MRS 

 constituents. In keeping with earlier discussion, Figures 21 and 24 are 

 considered poorly grouped cases. All but two (Figs. 20 and 29) of the remain- 

 ing figures for Columbia Light and South Pass, considered as reasonably well 

 grouped cases, have two or more prominent constituents which extend well above 

 the 10 percent level. IndividuEil constituents for South Haven are less dom- 

 inating, so those that extend above the 10 percent level are considered prom- 

 inent. Frequency spacings , ^fMRQ» between each adjacent pair of prominent 

 constituents are tabulated (Table 8). A modulation period, T^jng. can be 

 defined from the MRS analysis as the reciprocal of Afj^Q^g . Tj^pq values are 

 also given in the table along with ef and T^od ^®'?* 35). A plot of 

 (Fig. 43), despite considerable scatter, gives some evi- 



'MRS 



mod 



dence of a relationship between T^od ^^^ ^^^ spacing between frequency 

 constituents. From Figures 40 and 43, it is evident that 



"^MRS 



derived from 



the frequency spacing between constituents is comparable to TjuxS' Figure 43 

 also indicates a tendency for T^rs ^° ^^ longer than T h for actively 

 growing waves. 



Table 8. 



Frequency spacing between prominent 

 constituents from MRS analysis. 



Site 



Starting time f 

 MRS analysis 



or 



^^^MRS 

 (Hz) 



(Hz) 



''^MRS 

 (s) 



mod 

 (s) 



South Haven 



1700 





0.0100 



0.0162 



100 



62 



South Haven 



1720 





0.0029 



0.0214 



342 



47 



South Haven 



17A0 





0.0071 



0.0178 



141 



56 



South Haven 



1740 





0.0044 



0.0178 



227 



56 



Columbia Light 



1300 





0.0024 



0.0019 



417 



527 



Columbia Light 



1300 





0.0028 



0.0019 



357 



527 



Columbia Light 



1500 





0.0074 



0.0021 



135 



485 



Columbia Light 



1500 





0.0068 



0.0021 



147 



485 



Columbia Light 



1500 





0.0064 



0.0021 



156 



485 



Columbia Light 



1508.5 





0.0028 



0.0021 



357 



485 



South Pass 



1510 





0.0062 



0.0087 



161 



115 



South Pass 



1520 





0.0065 



0.0108 



154 



93 



South Pass 



1530 





0.0050 



0.0108 



200 



93 



South Pass 



1530 





0.0055 



0.0108 



182 



93 



South Pass 



1530 





0.0103 



0.0108 



97 



93 



South Pass 



1540 





0.0018 



0.0104 



556 



96 



South Pass 



1540 





0.0066 



0.0104 



152 



96 



63 



