Internal Waves' Role in Determining Probability Distribution of Coherent Integration Time Near 133 Hz and 3709 km in North Pacific Ocean

Abstract

The hypothesis tested is that internal gravity waves limit the coherent integration time of sound at 3709 km in the Pacific ocean at 133 Hz and a pulse resolution of 0.06 s. Five days of continuous transmissions at 2-min intervals are examined. The source and the receiver are mounted on the bottom of the ocean with timing governed by atomic clocks. Measured variability is only due to fluctuations in the ocean. A model for the propagation of sound through fluctuating internal waves is run without any tuning with data. Excellent resemblance is found between the model and data's probability distributions of integration time up to a day, which is the largest lag explored. The probability that the integration exceeds a day or more is about 0.15. The model underpredicts the probability of occurrence of integration times shorter than 10 min. However, the overwhelming agreement at longer times supports the conclusion that the standard spectrum of internal waves accurately explains almost all of the distribution of measured integration time.