Effects of the composition of suspended particles in water on the photosynthetically usable radiation and remote-sensing reflectance

The total suspended solids concentration of a water body, usually denoted as TSS, is a useful indicator of water quality. The TSS is often empirically related to the downwelling irradiance (Ed) and above-surface remote-sensing reflectance (Rrs). However, the same TSS can result from different particle compositions, which are described by the particle size distribution (PSD). This implies that knowledge of TSS alone, without knowledge of the PSD, among other quantities such as refractive indices of the suspended particles, is insufficient to accurately characterize the light fields. This work describes how Ed and Rrs for waters of various Junge-type PSDs are computed, so that the effects of the PSD on these quantities can be studied. We have used the radiative transfer software package Hydrolight to generate these optical quantities. Results indicate that the effects of the PSD are potentially significant, and that they manifest in the backscattering coefficient at 550nm.

Author dc:creator

• BOREDIN SAENGTUKSIN

• photosynthetically usable radiation, remote-sensing reflectance, mie scattering, particle size distribution, downwelling irradiance