Direction and speed of internal waves in SESAME II, and their effect on acoustic transmission

Abstract

Analysis of thermal data from SESAME II has revealed variations of both long and short durations. Variations of long durations have been clearly identified with tidal cycles, and are nearly identical at two thermal arrays 433 m apart in range, with no significant relative time lag between the two. Though a zero relative time lag would imply a southeastern direction for the wave vector, the long wavelengths involved and the short range between the arrays make such a prediction inconclusive. Variations of shorter durations arrive at the two arrays with a relative time lag that ranges between 5 and 26 min. Wavelet analysis has confirmed this time lag, and shows that it holds for a range of wavelengths. This puts constraints on the direction and speed of the short-duration components. The implications of these results on acoustic propagation will be discussed. [Work supported by ONR and NRL.]