Intensity Fluctuations in a Stochastic Medium

A representation of the ocean medium as a stack of very thin isosound velocity layers, stochastic in a part of their sound velocity, has been used to calculate the statistics for sound-intensity variation without introducing a random phase approximation. A model previously introduced [N. W. Lord, J. Acoust. Soc. Amer. 46, 111 (1969)] to calculate transmission-time statistics was extended first to treat intensity of discrete arrivals, quantitatively including phase differences among microarrivals, and second to accumulate at discrete range points all discrete arrival contributions similarly calculated and quantitatively including their mutual phase differences. Both discrete arrival intensities and accumulated or CW intensities show a Poisson-like distribution with standard deviation being equal to the mean for moderate sound velocity variance in rough agreement with existing data.