O 80 



100 



LANDS END 



WINTER PROFILE 



25 m SOURCE 



1000 



FREQUENCY, Hz 



Figure 4.1 1 . Propagation loss for opiimum receiver depth vs frequency for ranges of 50, 100 and 

 150 km. Lands End winter (positive gradient) profile; source depth 25 m. 



LANDS END 



SUMMER PROFILE 



SOURCE 25 m 



130 



100 



200 300 500 



FREQUENCY, Hz 



1000 



2000 



Figure 4.1 2. Propagation loss for optimum receiver depth vs frequency for ranges of 50, 100 and 

 150 km. Lands End summer profile; source depth 25 m. 



49 



