A Cross-Spectral Model Relating Fluctuations in Underwater Acoustic Phase to Environmental Parameters

摘要

The relationships between daily fluctuations in the phase of the complex propagation loss across the Straits of Florida and daily fluctuations in environmental parameters are quantitatively examined by means of cross-spectral analysis. A multi-input analytic model is suggested defined by its frequency response matrix, with deep and shallow water temperatures, tide-height, and wind components serving as inputs while two phases of the received signal measured at hydrophones 3 and 43 nautical miles, from the source serve as outputs. Analyses of the model are based on 3 months of continuous measurements of input and output data. The frequency response matrix is evaluated and residual spectra and multiple coherence functions are calculated. It is observed that variations in the deep water temperature and tide-height have the strongest coherence with the daily phase fluctuations. (Author)