SECT, 5] 



WIND WAVES 



677 



there is a band of activity tliat seems distinct from the rest of the spectrum. 

 The frequency of this band tends to increase throughout this series of spectra. 

 On examination, this change suggests a storm occurring at a distance of some 

 3000 miles and about 4 days before the first record in this series. Synoptic 



150 



23.00 



50 lOO 150 



CYCLES PER KILOSECOND 



Fig. 5. Wave spectra taken at Cornwall, England, in 1949. The curves are smoothed repre- 

 sentations of those in the literature. They plot mean amplitude (square root of power per 

 unit frequency interval) against wave frequency. The isolated low-frequency activity 

 attributed to the hurricane is distinguished in black. Its frequency shows some slight 

 oscillation attributable to the effect of tidal streams near the Cornish coast, but the 

 general trend toward higher frequencies is in accordance with the time and distance 

 of a hurricane reported off Florida. 



meteorological charts of the North Atlantic at this time showed a hurricane 

 passing out to sea from the coast of Florida, and this storm was no doubt 

 the cause of the long swell that was detected at Cornwall. The remainder of the 

 spectrum represents waves from less distant storm areas. 



Swell frequently causes severe damage to shore buildings and to the fishing 

 fleet in Barbados (Lesser Antilles). A study of the synoptic meteorological 



