Accession Number:

ADA230005

Title:

Detection and Source Localization of Singular Arctic Ice-Noise Producing Events

Descriptive Note:

Abstract

Corporate Author:

NAVAL OCEANOGRAPHIC AND ATMOSPHERIC RESEARCH LAB STENNIS SPACE CENTER MS

Report Date:

1990-01-01

Pagination or Media Count:

1.0

Abstract:

Detection and localization of single noise-producing comprising underwater Arctic ice noise are difficult due to myriads of sound sources present. This paper describes a recent experience gained while processing data from several horizontally placed hydrophones, where it has been shown that source localization of relatively nearby events 5,000-10,000 m is feasible under conditions favorable to individualization of single ice transients. Initial processing strives to isolate event ensembles comprised of a small number of concurrent events of magnitude well above background noise. The ensemble detector employed dynamically determines the ratio of short and long time base mean deviations. At a suitable adjustment of its time base parameters, a ratio of 10 to 20 ensures that this goal is achieved. Multichannel ensemble graphs are examined visually to select ensembles comprising the singular events required for time delay estimation and computation of source location. The procedure works well during time periods of low overall noise level, allowing nearby events to be separated in time. Keywords Sea ice, Underwater sound, Background noiseseparation, Underwater acoustics, Wave propagation, Arctic regions, Hydrophones, Noise analyzers, Acoustic detectors.

Subject Categories:

  • Snow, Ice and Permafrost
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE