Three-dimensional beam pattern of regular sperm whale clicks confirms bent-horn hypothesis
Zimmer, Walter M. X.
Tyack, Peter L.
Johnson, Mark P.
Madsen, Peter T.
MetadataShow full item record
KeywordBioacoustics; Biocommunications; Array signal processing; Echo; Hydrophones; Multidimensional signal processing; Underwater sound; Sonar signal processing
The three-dimensional beam pattern of a sperm whale (Physeter macrocephalus) tagged in the Ligurian Sea was derived using data on regular clicks from the tag and from hydrophones towed behind a ship circling the tagged whale. The tag defined the orientation of the whale, while sightings and beamformer data were used to locate the whale with respect to the ship. The existence of a narrow, forward-directed P1 beam with source levels exceeding 210 dBpeak re: 1 µPa at 1 m is confirmed. A modeled forward-beam pattern, that matches clicks >20° off-axis, predicts a directivity index of 26.7 dB and source levels of up to 229 dBpeak re: 1 µPa at 1 m. A broader backward-directed beam is produced by the P0 pulse with source levels near 200 dBpeak re: 1 µPa at 1 m and a directivity index of 7.4 dB. A low-frequency component with source levels near 190 dBpeak re: 1 µPa at 1 m is generated at the onset of the P0 pulse by air resonance. The results support the bent-horn model of sound production in sperm whales. While the sperm whale nose appears primarily adapted to produce an intense forward-directed sonar signal, less-directional click components convey information to conspecifics, and give rise to echoes from the seafloor and the surface, which may be useful for orientation during dives.
Author Posting. © Acoustical Society of America, 2005. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 117 (2005): 1473-1485, doi:10.1121/1.1828501.
Showing items related by title, author, creator and subject.
Morozov, Andrey K.; Preisig, James C.; Papp, Joseph C. (Acoustical Society of America, 2008-09)Acoustical array data from the Shallow Water Acoustics experiment was processed to show the feasibility of broadband mode decomposition as a preprocessing method to reduce the effective channel delay spread and concentrate ...
Piecewise coherent mode processing of acoustic data recorded on two horizontally separated vertical line arrays Udovydchenkov, Ilya A.; Brown, Michael G.; Duda, Timothy F. (Acoustical Society of America, 2012-05-25)Motivated by measurements made in the 2004 Long-Range Ocean Acoustic Propagation Experiment (LOAPEX), the problem of mode processing transient acoustic signals collected on two nearby vertical line arrays is considered. ...
The development and application of random matrix theory in adaptive signal processing in the sample deficient regime Pajovic, Milutin (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2014-09)This thesis studies the problems associated with adaptive signal processing in the sample deficient regime using random matrix theory. The scenarios in which the sample deficient regime arises include, among others, the ...