Effect of Natural Undisturbed Particle Fields on Light Transmission and Dispersion in Coastal Waters.
Abstract
Project Summary The volume scattering function (VSF) ? and absorption coefficient, a, are the inherent optical properties (IOPs) needed to predict and interpret transmission and dispersion of light through water (e.g., Kattawar et al., 1973; Zaneveld, 1991; Twardowski et al., 2005). In virtually all measurements and models we are aware of, the VSF is assumed to have no dependency on the direction of illumination or the azimuthal plane of scattered radiance. For this assumption to be true, all particles suspended in the water column must be randomly oriented. From simple physics of hydrodynamic flows for the nonspherical particles that comprise virtually all the particles in the ocean, this is not a reasonable assumption (e.g. Jefferey, 1922; Karp-Boss et al., 2000; Marcos et al. 2011). Furthermore, direct evidence from the field is confirming ubiquitous preferential particle alignment in coastal waters, particularly within density gradients (Malkiel et al., 1999; Talapatra et al., 2013). Consequently, it appears that our understanding of the geometry-dependent VSF, and thus light transmission through coastal waters is significantly biased. The three primary goals of this project are to: 1.1) gather both empirical and quantitative evidence showing that the in-situ orientation of sensors affects their resultant measurements; 1.2) gather statistical distributions detailing the spatial orientation of both large and small particles collected concurrently with the measurements needed for goal 1.1; and 1.3) conduct optical modeling studies using the non-random particle size and orientation statistics gathered for goal 1.2 and compare to models using the same particle size populations in random orientation. These modeling results can then be compared to instrument measurements taken as part of goal 1.1.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512628
Entities
People
- Fraser Dalgleish
Organizations
- Florida Atlantic University
- Office of Naval Research
- United States Navy