Long Range Ocean Acoustics and Synoptic Oceanography 

 Straits of Florida Results* 



John G. Clark and James R. Yarnall 

 Institute of Marine Science 

 University of Miami, Miami, Florida 33149 



INTRODUCTION 



The Straits of Florida acoustic-environmental measurement 

 system (Project MIMI)** has been thoroughly described in previous 

 publications; -I- > 2, 3 thus only a minimum of descriptive material need 

 be repeated here. An attempt has been made to present all of this 

 material in Figures 1 and 2, and Table I. Figure la provides for 

 geographical orientation; Figure lb presents a bottom profile of the 

 acoustic path with representative sound speed profiles computed from 

 hydrographic data available at the Institute of Marine Science;^ 

 Figure 2 identifies the field installations of the MIMI system. Ad- 

 ditional information regarding these installations is summarized in 

 Table I. 



By September of 1966 the system had matured sufficiently to 

 permit the start of a long period operation which lasted until 

 January 31, 1967. This long test has been designated "Lunar Cycle 

 Test One" (LCT-1) . Much of the data to be presented here were obtain- 

 ed during LCT-1. The two hydrophones given the special designations 

 H3 and H43 in Figure 2 will be referred to frequently in the follow- 

 ing discussions. The special designations are descriptive in that 

 the respective ranges of the hydrophones are approximately 3 and 43 

 miles from the acoustic source. 



Several types of acoustic signals are available for exper- 

 imental use in the Straits of Florida studies ;•'■ this report, however, 

 will be concerned only with the results of cw transmission at 420 Hz. 



The Straits of Florida studies are transmission experiments. 



* Contribution No. 798 from the Institute of Marine Science, 

 University of Miami. This research was sponsored by the U.S. 

 Office of Naval Research. 



** See acknowledgements. 



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