Accession Number : AD0890286

Title :   Shipborne Wave-Recorder Measurements of Surface Waves during Acoustic Experiments in the Western Ligurian Sea (ACOC-1).

Descriptive Note : Technical memo.,

Corporate Author : SACLANT ASW RESEARCH CENTRE LA SPEZIA (ITALY)

Personal Author(s) : Briscoe, Melbourne G.

Report Date : 01 OCT 1971

Pagination or Media Count : 25

Abstract : Waves were measured south of Monaco in February 1970. The data for the main experiment days of 12 and 17 February were analysed by a simple analysis technique to yield significant wave heights and periods; hourly wave spectra were also calculated for the 17 February data. On 12 February, when the winds were 5 knots or less throughout the day, the standard deviation of the surface displacements was 0.14 m during the morning and 0.11 m in the afternoon; average zero-upcrossing periods were 6.8 seconds changing to 7.6 seconds during the day. On 17 February, when conditions were slightly rougher, the winds were 10 knots in the morning growing to 35 knots by late afternoon, but strong fetch limitations held the standard deviation of surface displacements to 0.25 m; the average zero-upcrossing period was about 7.8 seconds. In terms of properly defined 'sea state' (World Meteorological Organization Code 3700) the conditions were SS 2 on 12 February and SS 3 on 17 February. Incorrect but common sea state estimates based on wind force instead of wave height would have been SS 0 and AA 3-4.

Descriptors :   (*HYDROGRAPHIC SURVEYING, RECORDING SYSTEMS), (*OCEAN WAVES, MEASUREMENT), ACOUSTIC EQUIPMENT, SHIPBOARD, SURFACE ROUGHNESS, WIND, UNDERWATER SOUND SIGNALS, REFLECTION, OCEANOGRAPHIC SHIPS, MEDITERRANEAN SEA, DATA PROCESSING, MAGNETIC TAPE, PROGRAMMING LANGUAGES, STATISTICAL ANALYSIS, POWER SPECTRA.

Subject Categories : Physical and Dynamic Oceanography
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE