Abstract:

During a recent experiment in the Southern California Bight region, recordings of vocalizing blue whales were made simultaneously by a vertical line array of 48 hydrophones and freely drifting, standard Navy sonobuoys. Vector acoustic intensity techniques are applied to the ``DIFAR'' sonobuoy data to determine azimuth versus time for two individual animals vocalizing in turn. Once the azimuths are determined, matched-field processing with a 2-D normal-mode code is applied to the vertical hydrophone array data to determine the animals' position in range and depth. These processing techniques used with the data from these two sensor systems permit investigations to be made of diving behavior, vocalization source levels, and calling interactions. [Work supported by ONR, Codes 341BST and 321OA.]