Acoustic pulse propagation in a fluctuating ocean with range-dependent sound-speed profile

Abstract

When an acoustic pulse propagates in a randomly fluctuating ocean with a deterministic sound-speed profile, it is distorted since every frequency component experiences different extents of scattering from the random inhomogeneity and echo numbers. Here, the split-step method is used to simulate an acoustic pulse with a 3-kHz carrier propagating through a turbulent ocean with range-independent/-dependent sound-speed profiles. It is found that ͑1͒ the ocean is a frequency-selective fading channel; ͑2͒ the received pulse profile is dependent on the received depth, sound-speed distribution, fluctuation strength, and scale length of turbulence in oceans; ͑3͒ the rms pulsewidth is broadened by several times its initial value as a consequence of pulse echoes and pulse wandering of every pulse realization of the ensemble; ͑4͒ the rms pulsewidth is increased when the fluctuation strength increases or the scale length decreases; and ͑5͒ the statistical properties of the propagating pulse are similar for both the range-independent and -dependent cases in the mean square sense.