MEAN HORIZONTAL SOUND SPEED TO THE FIRST CONVERGENCE ZONE IN NOVEMBER.
NAVAL RESEARCH LAB WASHINGTON D C
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Data on underwater one-way acoustic propagation times were collected during five traverses of the first convergence zone in the deep waters north of Puerto Rico. This data was obtained on three consecutive days in November 1958 by equipment located aboard two ships. The source ship utilized an acoustic transducer, transmitting 500-msec pulses at 1090 Hz, at depths of 20, 100, and 300 ft, and the receiving ship utilized a hydrophone at depths from 20 to 420 ft. The horizontal range between the ships varied from 68 to 79 kiloyards. The values of sound speed obtained at all depths ranged from 1639 to 1647 ydsec, increasing from the start to the end of the convergence zone. There was a significant change in the variability of sound speed values from one day to the next. Variations in the sound travel time measurements were least at the 420-ft depth. The mean horizontal sound speed derived from the measured data was compared with values computed from an exact ray trace solution and also from an approximation utilized in the correction of sonar data. There is a general correspondence between these calculations and experimental data within the first convergence zone. Author