Dolphin sonar transmissions and nonlinear effects.

Published work on dolphin sonar is utilized to model the short transient “clicks” used by the small-toothed whales for foraging, etc., in order to determine whether or not nonlinear acoustical effects play a role in dolphin sonar. Echolocation sound production in the bottlenose dolphin and the resulting underwater sonar signals is briefly reviewed. Nonlinear acoustic modeling with the Khokhlov–Zabolotskaya–Kuznetsov (KZK) nonlinear parabolic wave equation is described, along with the procedures used to employ measured signatures in modeling computations. Results for the bottlenose dolphin as well as several other species of small toothed whales indicate that propagating nonlinear acoustical effects in the water medium are not significant. [ABSTRACT FROM AUTHOR]