title: Range estimation of bowhead whale (Balaena mysticetus) calls in the Arctic using a single hydrophone.
abstract: Bowhead whales generate low-frequency calls in shallow-water Arctic environments, whose dispersive propagation characteristics are well modeled by normal mode theory. As each mode propagates with a different group speed, a call's range can be inferred by the relative time-frequency dispersion of the modal arrivals. Traditionally, at close ranges modal arrivals are separated using synchronized hydrophone arrays. Here a nonlinear signal processing method called "warping" is used to filter the modes on just a single hydrophone. The filtering works even at relatively short source ranges, where distinct modal arrivals are not separable in a conventional spectrogram. However, this warping technique is limited to signals with monotonically increasing or decreasing frequency modulations, a relatively common situation for bowhead calls. Once modal arrivals have been separated, the source range can be estimated using conventional modal dispersion techniques, with the original source signal structure being recovered as a by-product. Twelve bowhead whale vocalizations recorded near Kaktovik (Alaska) in 2010, with signal-to-noise ratios between 6 and 23 dB, are analyzed, and the resulting single-receiver range estimates are consistent with those obtained independently via triangulation from widely-distributed vector sensor arrays. Geoacoustic inversions for each call are necessary in order to obtain the correct ranges.
authors.affiliation: Lab-STICC, ENSTA Bretagne (Université Européenne de Bretagne) 2 rue François Verny, 29806 Brest Cedex 9, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Bonnel
authors.affiliation: Marine Physical Laboratory, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093-0238.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Thode
authors.affiliation: Greeneridge Sciences, Inc., 6160-C Wallace Becknell Road, Santa Barbara, California 93117.
authors.forename: Susanna B
authors.initials: SB
authors.lastname: Blackwell
authors.affiliation: Greeneridge Sciences, Inc., 6160-C Wallace Becknell Road, Santa Barbara, California 93117.
authors.forename: Katherine
authors.initials: K
authors.lastname: Kim
authors.affiliation: Shell Exploration and Production Company, 3601 C St #1000, Anchorage, Alaska 99503.
authors.forename: A Michael
authors.initials: AM
authors.lastname: Macrander
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D000818:Animals; D001110:Arctic Regions; D050642:Bowhead Whale / Q000502:physiology*; D009038:Motion; D009792:Oceans and Seas; D011312:Pressure; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D013016:Sound; D013018:Sound Spectrography; D013997:Time Factors; D014160:Transducers, Pressure; D014828:Vocalization, Animal