Estimation of Secchi-disk Depth Semi-analytically from Landsat-8 Data

Zhongping Lee1, Shaoling Shang2, Lin Qi3 and Jing Yan2, (1)University of Massachusetts Boston, Boston, MA, United States, (2)Xiamen University, Xiamen, China, (3)university of Massachusetts, Boston, School for the Environment, Boston, MA, United States
Abstract:
The newly developed analytical model [Lee et al., RSE, 2015] for Secchi disk depth (Zsd) is modified for application with Landsat-8 measurements. Also, to implement the quasi-analytical algorithm (QAA) for the derivation of absorption and backscattering coefficients from Landsat-8 data, which are key optical properties for the estimation of Zsd, the representative wavelengths of the Landsat-8 bands in the visible domain were determined; so were the absorption and backscattering coefficients of pure water at these bands. The semi-analytical scheme was further applied to a Landsat-8 image collected in an estuarine to obtain high-spatial resolution Zsd map, and the obtained results were found quite consistent with numerous visual perceptions. These results indicate the possibility to generate reliable high-resolution water clarity product of bays, estuaries, and lakes from Landsat measurements with a unified mechanistic system.