On the modeling of hyperspectral remote-sensing reflectance of high-sediment-load waters in the visible to shortwave-infrared domain

We evaluated three key components in modeling hyperspectral remote-sensing reflectance in the visible to shortwave-infrared (Vis–SWIR) domain of high-sediment-load (HSL) waters, which are the relationship between remote-sensing reflectance (Rrs) and inherent optical properties (IOPs), the absorption coefficient spectrum of pure water (aw) in the IR–SWIR region, and the spectral variation of sediment absorption coefficient (ased). Results from this study indicate that it is necessary to use a more generalized Rrs–IOP model to describe the spectral variation of Rrs of HSL waters from Vis to SWIR; otherwise it may result in a spectrally distorted Rrs spectrum if a constant model parameter is used. For hyperspectral aw in the IR–SWIR domain, the values reported in Kou et al. (1993) provided a much better match with the spectral variation of Rrs in this spectral range compared to that of Segelstein (1981). For ased spectrum, an empirical ased spectral shape derived from sample measurements is found working much better than the traditional exponential-decay function of wavelength in modeling the spectral variation of Rrs in the visible domain. These results would improve our understanding of the spectral signatures of Rrs of HSL waters in the Vis–SWIR domain and subsequently improve the retrieval of IOPs from ocean color remote sensing, which could further help the estimation of sediment loading of such waters. Limitations in estimating chlorophyll concentration in such waters are also discussed.