Accession Number:

ADA614287

Title:

Optics, Acoustics and Stress in a Nearshore Bottom Nepheloid Layer

Descriptive Note:

Final rept. 1 Dec 2009-30 Sep 2013

Corporate Author:

DALHOUSIE UNIV HALIFAX (NOVA SCOTIA) DEPT OF OCEANOGRAPHY

Personal Author(s):

Report Date:

2014-12-12

Pagination or Media Count:

7.0

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.

Subject Categories:

  • Physical and Dynamic Oceanography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE