Optics, Acoustics and Stress in a Nearshore Bottom Nepheloid Layer

Abstract

The attenuation of light near the seabed in the coastal ocean is affected by the concentration, size and composition of suspended particulate mass. Our research demonstrated that the effect of size is reduced considerably by the packaging of suspended particles into particle aggregates for which particle mass scales with particle area rather than with particle volume. Reduced sensitivity to size makes light attenuation a useful proxy for suspended particulate mass in many environments. Variation is the attenuation to mass ratio, however, does exist among and between environments, however, and the source of the variation remains unclear. Our research demonstrated that, on average, variable particle composition accounts for a factor of two variation in the beam attenuation to mass ratio, which does not fully explain observed variation. This finding indicated that particle packing geometry determines the light scattering properties of particles. Initial analysis of an optical proxy for particle packing geometry showed some promise.

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Document Details

Document Type
Technical Report
Publication Date
Dec 12, 2014
Accession Number
ADA614287

Entities

People

  • Paul Hill

Organizations

  • Dalhousie University

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustics
  • Attenuation
  • Boundaries
  • Boundary Layer
  • Earth Sciences
  • Environment
  • Geometry
  • Layers
  • Marine Geology
  • Measurement
  • Nova Scotia
  • Oceanography
  • Optical Properties
  • Particle Size
  • Particles
  • Remote Sensing
  • Suspended Sediments

Fields of Study

  • Environmental science
  • Physics

Readers

  • Acoustical Oceanography.
  • Marine Ecotoxicology
  • Materials Science and Engineering.