Accession Number : ADA131678

Title :   The Arctic Channel: An Acoustic Waveguide.

Descriptive Note : Technical memo.,

Corporate Author : NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CT NEW LONDON LAB

Personal Author(s) : DiNapoli,F R

PDF Url : ADA131678

Report Date : 25 Apr 1978

Pagination or Media Count : 12

Abstract : The Arctic Basin provides a unique channel for acoustic propagation. The two features peculiar to the polar environment that most strongly influence the transmission of underwater sound are the permanent ice cover and the uniform sound speed structure. As a result, only a few low order modes will propagate through it to great distances and the non-linear frequency dependent time delay of the channel may be accurately computed. In the Arctic channel, the disperson is such as to prodce a 'chirp' frequency modulation on a transmitted pulse. Consequently the channel itself may be used as the matched receiving filter by transmitting a time reversed (chirped) waveform and letting the dispersion effect compress the waveform. This process will be strictly range dependent. (Author)

Descriptors :   *Acoustic channels, *Arctic Ocean, *Sound transmission, Frequency modulation, Sea ice, Acoustic velocity, Very low frequency, Long range(Distance), Pulse compression, Matched filters, Waveguides, Mathematical prediction, Fast fourier transforms, Wave propagation

Subject Categories : Physical and Dynamic Oceanography
      Numerical Mathematics
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE