OLCI remote sensing monitoring method for shallow lake inherent optical parameters

Abstract

The invention provides an OLCI remote sensing monitoring method for shallow lake inherent optical parameters; the method comprises the steps: based on a quasi-analytical algorithm, assuming that 750 nm water body total absorption is equal to pure water absorption, and establishing the relationship of the water body remote sensing reflectance ratio and the total absorption coefficient, and the relationship of the water body remote sensing reflectance ratio and the backscattering coefficient; according to the characteristics of absorption coefficients of all water body components and the relationships of the absorption coefficients with remote sensing reflectance ratio spectra and the backscattering coefficient, further resolving the water body total absorption coefficient into the absorption coefficients of the water body components; combining the water body remote sensing reflectance ratio spectra and the corresponding water body component absorption coefficients measured by Chaohu lake, Taihu lake and Hongze lake field tests, establishing IOP inversion algorithms facing to different lakes with complex water body optical characteristics based on the field actually measured spectra;and extending the IOP inversion algorithm to OLCI image data corrected by 6S atmosphere, and realizing remote sensing monitoring of the water body inherent optical parameter spatial distribution of eutrophic shallow water lakes.

Description

technical field [0001] The invention relates to an OLCI remote sensing monitoring method for intrinsic optical parameters of shallow lakes. Background technique [0002] Inherent Optical Properties (IOPs) of water body refers to the quantity that is only related to the water body medium and has nothing to do with the surrounding light field (Mobley, 1994), including absorption coefficient a, scattering coefficient b, and backscattering coefficient b b , volume scattering function β (Volume Scattering Function, VSF), attenuation coefficient c, single scattering albedo ω 0 , Specific absorption coefficient, etc. Among them, the basic intrinsic optical quantity is the absorption coefficient a and the volume scattering function β, and other IOPs can be obtained from the relationship between the two: [0003] [0004] c(λ)=a(λ)+b(λ) (2) [0005] [0006] Morel et al. (1977) divided the water body into the first type of water body and the second type of water body. The fi...

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Problems solved by technology

The composition and sources of optically active substances in the second type of water are complex, and there is no correlation between them, resulting in more complex optical properties of the water.

[0015] The complexity of the optical properties of the second type of water poses challenges to the precision and accuracy of the water quality parameter inversion model, which requires a deeper understanding of the physical driving or hydrodynamic mechanism of the optical properties of water in a region (Aurin et al., 2010)

[0016] At present, the main problems in remote sensing monitoring of key parameters of lake water environment (water temperature, transparency, chlorophyll concentration, suspended solid concentration, etc.) are: (1) The optical characteristics of lake water are complex, and there are large differences between different lakes, making it difficult to establish Unified inversion algorithm for water quality parameters; (2) The impact of key parameters of lake water environment on global climate change and human activities is not clear

The same water quality parameter inversion algorithm is difficult to apply to different lake water bodies. The reason is that the sources and compositions of algae in lakes are complex, or the large amount of suspended sediment brought by rivers into lakes leads to relatively large changes in the specific absorption and specific scattering coefficients of water body components. large, which directly leads to the inefficiency of some models based on the assumption that the specific absorption coefficient is constant

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