LONG TERM GOALS

The goal is to better understand fluctuating sound propagation in two distinct ocean acoustic regimes: Stratified shallow water, where sound is highly bottom interacting, and the temperate deep-ocean sound channel. Acoustic field fluctuations have time scales varying from less than a minute to hours, and horizontal spatial scales from tens of meters to kilometers, comparable to processing time scales and system spatial scales, and thus impact exploitation of underwater sound. With proper understanding, reliable predictions of temporal and spatial variability of received underwater sound may be possible, thus improving processing and handling of signals of interest. Processing could include remediation of signal degradation and/or exploitation of available sonic information. OBJECTIVES An objective is to quantify and explain underwater sound fluctuation behavior that has been observed in both shallow and deep regimes, for the purpose of meeting the stated goals. For shallow water, transmission loss and phase data are available at frequencies from 50 to 3000 Hz. For the deep-ocean sound channel, data are in hand for propagation at 50 to 100 Hz over 100’s to 1000’s of kilometers. Propagation and forward scattering models, both theoretical and computational, will be used to tes