Peter N. Mikhalevsky
Sci. Appl. Intl. Corp., McLean, VA 22102
Arthur B. Baggeroer
MIT, Cambridge, MA 02139
Andreev Inst. of Acoust., Moscow, Russia
Inst. of Appl. Phys., Nizhny Novgorod, Russia
In the spring of 1994 a series of cw and maximal length sequences (M sequences) were transmitted 2600 km across the Arctic Ocean. The transmissions were centered at 19.6 Hz from a Russian source located 300 km north of the Svalbard Archipelago. The transmissions were received in the Lincoln Sea (900-km range) on a 32-element vertical line array and in the Beaufort Sea (2600-km range) on a 32-element vertical line array and a 32-element horizontal planar array. Analysis of the transmission loss, phase stability, array gain, and pulse compression gain are being used to develop an acoustic monitoring strategy in the Arctic for climate studies. The exceptional stability of the Arctic sound channel first noted in the early 1980s [P. N. Mikhalevsky, J. Acoust. Soc. Am. 70, 1717 (1981)] make acoustic thermometry potentially a very sensitive indicator of Arctic Ocean temperature and ice changes.