SOUND VELOCITY STRUCTURE OF THE OCEAN BETWEEN 



BERMUDA AND THE ANTILLES 



by 



R. E. Payne and J. C. Beckerle 

 Woods Hole Oceanographic Institution, Woods Hole, Mass. 02543 



INTRODUCTION 



The Geophysics Department of the Woods Hole Oceanographic Institution 

 is conducting a continuing study to determine the variations of the sound 

 velocity structure of the broad ocean area between Bermuda and the 

 Antilles as a function of time and of the geographical coordinates. The 

 first survey in this study was made in July and August of 1962 by J. Reitzel. 

 During the same months of 1964 we made a large number of sound velocity 

 profiles on Cruise 11 of the R/V ATLANTIS 11. Figure 1 shows the 

 positions of the profiles made in the two studies. The large dots are 

 posiiions of profiles in 1962; the small dots and the large dots with numbers 

 are positions of profiles in 1964. We chose the positions of our profiles 

 so as to give a broad coverage of the area and also to give some detailed 

 information about areas which appeared to be interesting in 1962. The 

 numbers at the positions give the profile numbers. Sound velocities were 

 measured with a commercial model of the National Bureau of Standards 

 "sing - around" velocinieter. Depths were measured with an Inverted 

 Echo Sounder, (Dow, 1963) using the measured sound velocities to correct 

 the depths. Sound velocities were calculated at 1 to 2 meter depth intervals 

 with the assistance of a GE 225 computer. 



SHORT TERM VARIATIONS 



We were interested in learning the magnitude of fluctuations of sound 

 velocity at any given depth that may take place within the duration of a 

 cruise. This information is necessary to determine within what limits 

 we can compare profiles made at different times in a cruise. To this end 

 we made three pairs of lowerings, the two members of a pair being made 

 at locations as close as was practical, 7 miles apart in the worst instance 

 and 1 mile in the best. Figure 2 shows Profiles 21 and 22 which were 

 made in the Puerto Rican Trench about 6 hours apart. Although the 



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