John L. Spiesberger
Dept. of Meteorol. and the Appl. Res. Lab., 512 Walker Bldg., Penn State Univ., University Park, PA 16802
Fluctuations and uncertainties in winds (currents) and sound speed place lower limits on the accuracy with which calling animals can be passively localized from their calls in terrestrial and marine environments. The most accurate acoustic passive localizations of animals require simultaneous mapping of these environmental fluctuations using tomographic techniques [J. Spiesberger and K. Fristrup, Am. Nat. 135, 107--153 (1990)]. One localization experiment conducted in a wood found tomographic localization of a cap gun possible but tomographic localization of birds difficult because of echoes. Marine environments may be conducive to tomographic localizations because of a paucity of reflecting surfaces at low frequencies. A new oceanographic instrument called a surface suspended acoustic receiver (SSAR) has the potential for passively localizing and censusing calling animals throughout the world's oceans in real time. [Work partially supported by Advanced Research Projects Agency.]