Accession Number : AD0694296

Title :   DIURNAL VARIATIONS IN UNDERWATER NOISE BENEATH SPRINGTIME SEA-ICE,

Corporate Author : DEFENCE RESEARCH ESTABLISHMENT PACIFIC VICTORIA (BRITISH COLUMBIA)

Personal Author(s) : Milne,A. R. ; Ganton,J. H.

Report Date : 06 JAN 1969

Pagination or Media Count : 5

Abstract : Underwater ambient noise in ice-covered seas can show a dependence on air temperature. This temperature dependence is particularly striking in spring in the latitudes of the Canadian Arctic Archipelago where the air temperatures are, in turn, dependent on the altitude of the Sun. The upper curve shows the air temperature plotted against time of day during the period April 16 to April 27. The lower bar-graph is an underwater noise pressure record in the 150-300 Hz band on the same time scale. The envelope of the bar-graph shows diurnal variations similar to the expected diurnal temperature variations of air temperature, but shifted in phase by approximately 180 degrees. (Author)

Descriptors :   (*SEA ICE, ARCTIC REGIONS), (*UNDERWATER SOUND, DIURNAL VARIATIONS), ATMOSPHERIC TEMPERATURE, CRACKS, TENSILE PROPERTIES, STRESSES, CONTRACTION, SNOW, PRESSURE, CANADA

Subject Categories : Snow, Ice and Permafrost
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE