Accession Number:

ADA224808

Title:

Acoustic Reflections from Cylindrical Blocks on Arctic Ice, 1988

Descriptive Note:

Technical rept. 18 Feb-8 Mar 1988,

Corporate Author:

WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB

Report Date:

1990-01-01

Pagination or Media Count:

81.0

Abstract:

In the spring of 1988 acoustic reflections were measured from the submerged ends of cylindrical blocks of arctic ice, in an extension of similar efforts in 1984 and 1986. Blocks with diameters of 27, 38, 58, and 84 cm were individually depressed below the surface of the ice floe so the reflections from the bottoms of the blocks were separable from those off the underside of the ice canopy. The sourcereceiver was moved horizontally beneath the block to measure the angular response pattern. Measurement to determine the effect of the so- called skeletal layer showed that, compared with solid ice, the layer reduced the reflection at normal incidence by 8-11 dB in the frequency range 20-80 kHz for all blocks. Properties of the skeletal layer and the transition zone were also measured to study the nature of the reflection. EDC

Subject Categories:

  • Snow, Ice and Permafrost
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE