CE HO - 



200 



300 500 



FREQUENCY, Hz 



1000 



4000 



Figure 4.28. Cylindrical spreading loss plus absorption loss in the water as a function of frequency for 

 fixed ranges of 50, 100 and 150 km. 



Strait of Juan de Fuca above 300 Hz (Figure 4.6) 

 East of Singapore above 1000 Hz (Figure 4.9) 



• Summer and Intermediate Profile Cases 



Nortli Sea around 300 Hz (Figures 4.2, 4.3) 



• Fall Profile Case 



Strait of Juan de Fuca above 900 Hz (Figure 4.8) 

 Examples in other areas are; 



• Winter Profile Cases 



Korea Strait above 600 Hz (Figure 4.13, sand layer) 

 Korea Strait above 400 Hz (Figure 4.15, no sand layer) 

 Straits of Sicily above 100 Hz, 500 m depth (Figure 4.18) 

 Straits of Sicily around 300-400 Hz, 1 65 m depth (Figure 4. 1 6) 



We find a surface duct or a nearby lossless bottom reflected duct in each of these 

 cases. 



65 



