RODERICK: FORWARD SCATTERED LOW-FREQUENCY SOUND FROM THE SEA SURFACE 



of sidelobes, and the narrow beamwidth of the major lobe. A 10-inch 

 diameter piston transducer operating at a reasonable frequency of 

 approximately 250 kHz was used as a source. 



Figure 16 displays recordings of wave height versus time measured 

 at five discrete points on the sea surface. The sensors are posi- 

 tioned in a line array and, if you look closely, you can see the phase 

 relationship as the surface waves propagate across the array. 



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