Simulation of backscattering properties of particles and the effect of its variability on estimation of TSM using bio-optical model: A case study of Lake Taihu in spring, China

Abstract

Backscattering coefficient is an important inherent optical property and it is also a basic parameter of bio-optical model. The in situ remote sensing reflectances and absorption coefficients measured in April 2009 were used to deduce backscattering coefficients of particles combined with bio-optical model. Then we analyzed the backscattering and specific backscattering characteristics of Lake Taihu in spring and the effect of variability of specific backscattering coefficients on estimation of TSM using bio-optical model. The results show that the backscattering coefficients of particles have a strong correlation with the concentration of total suspended matters and inorganic suspended matters, but a relatively weak correlation with the concentration of organic suspended matters. The specific backscattering coefficients co-vary with the backscattering coefficients, and differ a lot in space distribution while this variability may bring average relative errors of about 20% and root-mean-square errors (RMSE) of about 20mg/L. It is suggested that in order to obtain quantitative estimates of TSM in turbid waters from space, it is necessary to pre-determine specific backscattering efficiencies for the study area.