The Optical Properties And Turbidity Retrieval In Typical Highly Turbid Waters

The optical properties of highly turbid waters(ie.,Suspended Particulate Matter?SPM?in 10¹000+g?m^-3 or turbidity in 11¹110+NTU)and turbidity retrieval in such turbid waters were studied.The main researches of the thesis are as follows:1)A tank experiment was designed to discuss the impact of mineral composition on optical properties in coastal waters.The results show that when in the same concentration,the absorption coefficient of clay mineral varies.It suggests that the absorption coefficient of clay mineral is not only connected to the SPM concentration,but also mineral composition.2)Evidence of water reflectance saturation in extremely turbid media is highlighted based on both field measurements and satellite data corrected for atmospheric effects.This saturation is obvious in visible spectral bands,i.e.,in the blue,green and even red spectral regions when the concentration of suspended particulate matter?SPM?exceeds 100 g?m^-3.The Nechad-type relationship is selected to model the progressive saturation of R_rs in visible spectral bands and determine an objective criterion for saturation.The validity of several bio-optical semi-analytical models is assessed in the case of highly turbid waters,based on comparisons with outputs of the Hydrolight radiative transfer model.The most suitable models allow to reproduce the observed saturation and,by inversion,to retrieve information on the SPM mass-specific inherent optical properties.3)Meter scale satellite data was applied to highly turbid waters to retrieve turbidity and useful information.We made first evaluation of the performance of Pléiades image in estuary and coastal water by comparing to 20 m SPOT-like and 250m MODIS-like resolution images.The results show that Pléiades has a 2 m spatial resolution and covers more detail features,rendering it more suitable for application in the studies of fine-scale features such as Pauillac autonomous station turbidity monitoring and strong spatial variation environments such as MTZ?test site 1?detecting.However,Pléiades doesn't outperform SPOT-like and MODIS-like images in the river mouth?test site 2?.Then,Pléiades imagery with very high resolution shows its potential in new applications.