Accession Number:

ADB197442

Title:

Three-Dimensional Distribution of Sound Speed in the Iceland-Faeroe Area, Retrieved from a CTD Survey, Thermistor-Chain Measurements and Satellite SST Imagery

Descriptive Note:

SACLANTCEN rept.

Corporate Author:

SACLANT UNDERSEA RESEARCH CENTRE LA SPEZIA (ITALY)

Personal Author(s):

Report Date:

1994-11-01

Pagination or Media Count:

51.0

Abstract:

The three-dimensional variability of sound speed in the Iceland-Faeroe Frontal IFF region is investigated. Emphasis is put on the question, to what extend subsurface sound speed may be determined from space-borne remote sensing. Data from different sources are used CTD survey and thermistor-chain measurements as ground truth and satellite infrared imagery. Most of the data are temperatures which, for the area under consideration, quite accurately determine the sound speed. From the subsurface data it is shown that the vertical sound-speed profiles can be decomposed into empirical orthogonal eigenfunctions EOFs, with the first two already accounting for 97 of the variance. High correlation of the first- and second-order EOF amplitudes is found with sea-surface dynamic height, and for the first-order EOF amplitude with sea-surface temperature SST. The latter relation is used successfully to determine subsurface sound speeds from satellite-measured SSTs. Due to the resolution of the satellite data, horizontal scales are overestimated, and due to the availability of only the first-order EOF amplitude for the construction of sound-speed profiles, a too high vertical correlation is introduced. To overcome these problems, for the purpose of acoustic modelling, a theoretical three-dimensional sound-speed model is developed, based on the EOF decomposition. The EOF amplitudes contain the analytically described front and random portions represented by a finite moving average process.

Subject Categories:

  • Physical and Dynamic Oceanography
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE