McLeroy-Etheridge, S. L. University of Connecticut, stm98002@uconnvm.uconn.edu
Bontempi, P. L. GSO/University of Rhode Island, bontempi@gsosun1.gso.uri.edu

 
INTENSIVELY LEARNING OPTICAL OCEANOGRAPHY: INVESTIGATION OF CLOSURE BETWEEN MEASURED SCATTERING EFFICIENCIES AND THOSE DERIVED FROM THEORY
 
Pigment-specific scattering and backscattering coefficients (b*, bb*) are used to interpret variability in the inherent optical properties and in ocean color. However, not all particles that scatter light contain chlorophyll, and the size and index of refraction of a particle determine how light is scattered. Therefore, in order to interpret accurately b* and bb*, it is necessary to understand scattering properties. As a first step, closure between theory and measurement is necessary. In August 1998, scattering (b) and backscattering (bb) of waters in East Sound, Washington were measured using a WETLabs ac9 and HOBILabs hydroscat-6, respectively. Particle size distributions (PSD) and spectrophotometric measurements of discrete water samples provided input parameters for calculations of optical efficiency factors, b, and bb based upon Mie theory. Theoretical backscattering efficiencies (bb/b) agreed well with measured efficiencies; however, modeled b and bb coefficients underestimated those measured by an order of magnitude. Sensitivity analyses of the modeled coefficients to input parameters identified that the source of variability likely results from a missing fraction of large size particles or a particle concentration error. By investigating sources of error in closure, true variability in b* and bb* can be assessed accurately.
 
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
 
Code: SS53TH0562S