Abstract:
Large amplitude underwater acoustic signals, such as those produced by earthquakes and nuclear tests, can be monitored on a global scale using a limited network of underwater acoustic sensors. The design and operation of such a network requires an understanding of the limits on localization accuracy due to sound speed fluctuations in the ocean. For localization based on time of flight, the variance of the arrival time of the individual modes may be estimated by a range and depth integral over the sound-speed fluctuation statistics of the water column. Results obtained for travel time variance using this approach are compared to simpler measures such as the variance of the sound axis slowness integrated over a geodesic path. These results are in turn utilized to estimate the localization areas of uncertainty for a variety of source and receiver scenarios. All results are based on measured sound-speed statistics obtained from various ocean databases. [Work supported by DOE and Air Force Phillips Laboratory.]