Evaluating the Sonic Layer Depth Relative to the Mixed Layer Depth

Abstract

Using a global set of in situ temperature and salinity profile observations, the sonic layer depth (SLD) and the mixed layer depth (MLD) are analyzed and compared over the annual cycle. The SLD characterizes the potential of the upper ocean to trap acoustic energy in a surface duct while MLD characterizes upper ocean mixing. The SLD is computed from temperature and salinity profile pairs using a new tunable method while MLD is computed using recently developed methods and either temperature only profiles or temperature and salinity profile pairs. Both SLD and MLD estimates provide information on different and important aspects of the upper ocean. The SLD and MLD often coincide because sound speed increases with depth down to the MLD, where (typically) a decrease in temperature occurs, resulting in a local maximum sound speed. The depth of this maximum sound speed is the SLD.

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Document Details

Document Type
Technical Report
Publication Date
Jul 24, 2008
Accession Number
ADA484791

Entities

People

  • Charlie N. Barron
  • Michael R. Carnes
  • Robert A. Zingarelli
  • Robert W. Helber

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Acoustic Communications
  • Acoustic Properties
  • Acoustic Waves
  • Acoustics
  • Climate Change
  • Environment
  • Frequency
  • High Latitudes
  • Latitude
  • Longitude
  • Northern Hemisphere
  • Observation
  • Oceanography
  • Oceans
  • Salinity
  • Signal Processing
  • Transmission Loss

Readers

  • Fluid Dynamics.
  • Oceanography.