Accession Number:

ADA324660

Title:

Site Survey For on Ocean Engineering Project West of Perth for July to September 1992.

Descriptive Note:

Technical rept.,

Corporate Author:

DEFENCE SCIENCE AND TECHNOLOGY ORGANIZATION CANBERRA (AUSTRALIA)

Report Date:

1996-11-01

Pagination or Media Count:

138.0

Abstract:

Oceanic environmental surveys were made by DSTO off Perth, Western Australia over July to September 1992 to assess site suitability for an Underwater Radiated Noise Range for the Royal Australian Navy. Acoustic ranges are required to measure the noise radiated from ships and submarines. Salient factors for range design and performance include ambient noise, currents, topography and nature of the seafloor, water properties, wave, wind, and weather conditions. Measurements of these parameters indicate that the waters off Perth for bottom depths of 400 m are a difficult regime in which to construct and operate an acoustic range. High currents with strong vertical and horizontal shear were experienced, with directions varying through the water column, and with surface and bottom flows sometimes in opposite directions. Temperature micro-structure caused by meeting of warm, low salinity northern Leeuwin Current waters with cool, high salinity southern waters is predicted to cause fluctuations in intensity of acoustic signals. Ambient noise is significantly affected by rain, migrating whales, and shipping. Significant wave heights over 7 m were measured in August 1992. The environmental results are of general interest, and are presented for use by the wider scientific community.

Subject Categories:

  • Marine Engineering
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE