Results are presented in Sections 3 and 4. Section 3 contains the physical descrip- 

 tions of the sites, the representative profiles, a summary of the sound speed profile statistics 

 and bottom sediment characteristics. Acoustic results are given in Section 4 where propa- 

 gation loss calculations are presented and comparisons are made. Optimum frequencies 

 for the representative, seasonal profiles are discussed. Concluding remarks are given in 

 Section 5. 



2. PROCEDURES 



2. 1 Site Selection 



The locations of the shallow water areas discussed in this report are given in 

 Table 2.1. These sites were selected for evaluation based on expected differences in environ- 

 mental types. Selection is hmited in part by availability of sound velocity profile (SVP) 

 data in data banks and/or available sea floor sediment data. Of course, this is only a partial 

 list of possible shallow water sites of interest to the Navy. A more complete list might 

 contain 30-40 individual sites. 





Site 



Latitude 



Longitude 



A. 



North Sea 



57.5°-59.0°N 



1.5°-2.5°E 



B. 



Strait of Juan de Fuca 



48°-49°N 



125°-126°W 



C. 



East of Singapore 



0-2°N 



105°-109°E 



D. 



Lands End 



49°-51°N 



8°-10°W 



E. 



Korea Strait 



32°-34°N 



126.5°-128.5°E 



F. 



Straits of Sicily 



36°-38°N 



11°-13°E 



G. 



Shallow of Bering Sea 



56°-59°N 



165°-169°W 



H. 



Bass Strait 



39°-41°S 



145°-149°E 



I. 



North Coast of BrazU 



0°-2°N 



46.5°-49°W 







2°-4°N 



47.5°-50°W 



Table 2.1 . Locations of shallow water sites. 



The first four sites (Table 2.1) were chosen in 1980 for a preliminary study. The Strait of 

 Juan de Fuca represents a mid latitude site coupled strongly with the open ocean with 

 potential brackish water influence. The site East of Singapore is an example of an equatorial 

 environment within a large area of shahow water. Seasonal effects at low latitudes are 

 naturally expected to be weak compared to those at mid to high latitudes. The shallow 

 North Sea site is an example of an isolated adjacent sea located at high latitudes. The Lands 

 End site is positioned on a wide (continental) shelf at relatively high latitudes, exposed to 

 open ocean conditions and influenced by the North Atlantic current extension of the Gulf 

 Stream. 



The sites in the Straits of Sicily and the Korea Strait were added as areas of high 

 operational interest. The submarine ridge between Sicily and the continent of Africa, the 

 Straits of Sicily, separates the Mediterranean into two main basins. The eastern basin is a 



