Curve Fitting In Order Research Articles

Statistical Analysis of Random Components of Speed of Sound

Experimental data on the speed of sound variation with depth off the Florida Coast was statistically analyzed in order to obtain its characteristics and then to calculate their effect on ray tracing in ocean. The typical exponential depth decay of the speed of sound was removed by curve fitting in order to separate its randomly varying components. The experimental data were taken for depths up to 550 ft with an accuracy of 0.5 m/sec. The results of this work show that the probability distribution of the random component of the speed of sound is multimodal rather than of the usually expected normal form. Furthermore, the variance of the random component varies from a few tenths to up to 4 m/sec. The decorrelation distance of this random variation varies from 25 to 70 m, indicating a gross size of volume where temperature changes are correlated. This may be due to a transient temperature front or due to a volume perturbation in a stationary temperature distribution. Thus the importance of the random variations in the measurement of the speed of sound must be taken into account.