Mass-specific scattering coefficient for natural minerogenic particle populations: particle size distribution effect and closure analyses

摘要

The relationship between the particulate scattering coefficient (b_(p)) and the concentration of suspended particulate matter (SPM), as represented by the mass-specific scattering coefficient of particulates (b_(p)~(*) velence b_(p)/SPM), depends on particle size distribution (PSD). This dependence is quantified for minerogenic particle populations in this paper through calculations of b_(p)~(*) for common minerals as idealized populations (monodispersed spheres); contemporaneous measurements of b_(p), SPM, and light-scattering attributes of mineral particles with scanning electron microscopy interfaced with automated image and x-ray analyses (SAX), for a connected stream-reservoir system where minerogenic particles dominate b_(p); and estimates of b_(p) and its size dependency (through SAX results-driven Mie theory calculations), particle volume concentration, and b_(p)~(*). Modest changes in minerogenic PSDs are shown to result in substantial variations in b_(p)~(*). Good closure of the SAX-based estimates of b_(p) and particle volume concentration with bulk measurements is demonstrated. Converging relationships between b_(p)~(*) and particle size, developed from three approaches, were well described by power law expressions.