Estimation of Secchi Transparency in Turbid Coastal Waters

Abstract

The estimation of water clarity in terms of Secchi disk transparency is important for assessing water quality in coastal and various in-land water bodies. In this work, we have developed a new method to estimate underwater visibility depth, commonly known as the Secchi disk transparency (Zsd). The input parameters for this model include turbidity (NTU), vertical diffuse attenuation coefficient Kd (m-1), and beam attenuation coefficient c (m-1). The turbidity parameter is used to redefine the coupling coefficient. The successful validation of this model is achieved at a wavelength of 520 nm using independent dataset obtained from relatively clear and turbid waters. The performance of the present model was evaluated in terms of various statistical parameters which included MRE∼-0.012 and RMSE∼0.073, with approximately bias and slope of 0.004 and ∼1 respectively