MODIS satellite high-precision monitoring method for chlorophyll-a in eutrophic lake water body

Abstract

The invention provides an MODIS satellite high-precision monitoring method for chlorophyll-a in a eutrophic lake water body. The method comprises the following steps: screening a chlorophyll-a evaluation index (BNDBI) which is sensitive to the concentration change of chlorophyll-a and not affected by highly suspended matters, thin cloud and solar flares; acquiring the quantitative relationship between BNDBI and the concentration of chlorophyll-a on the basis of biological optical model simulation; acquiring a chlorophyll-a inversion algorithm based on ground measured spectrum (Rrs) and BNDBI by referring to water body spectral information and corresponding water body chlorophyll-a concentration of 2013-2014 lake field monitoring; acquiring the quantitative relationship between the ground monitoring and remote sensing reflectance ratio (Rrs) and Rrc after simulated Rayleigh scattering correction by simulating different aerosol types and thicknesses and different solar elevation angles, satellite observation angles and azimuth angles; and extending the chlorophyll-a inversion algorithm based on ground measured spectrum data to satellite image data after Rayleigh scattering correction. Based on the method, inter-annual and inter-monthly change rules and spatial distribution of chlorophyll-a in a eutrophic lake can be acquired accurately.

Description

technical field [0001] The invention relates to the technical field of remote sensing, in particular to a MODIS satellite high-precision monitoring method for chlorophyll a in eutrophic lake water. Background technique [0002] Remote sensing technology is widely used to monitor water eutrophication and algal blooms, which greatly improves the real-time monitoring ability of water quality (Matthews, 2010; Odermatt et al., 2012). Chlorophyll a (Chla, μg / L) is an important indicator of algal bloom intensity and water quality and nutritional status, and has become the most common parameter in water quality remote sensing (Chaeffer et al., 2012; Matthews, 2010; Qi et al., 2014). In recent years, due to the frequent occurrence of algal blooms, there has been a serious threat to the quality of drinking water and irrigation water (Duan et al., 2009; Guo, 2007), and the use of remote sensing to monitor water body chlorophyll a has quickly become a research hotspot (Paerl & Huisman, ...

AI Technical Summary

Problems solved by technology

First of all, the existing MODIS Chla algorithm (such as OC2, OC3, OC4 and OCI, etc.) is not suitable for highly turbid eutrophic water bodies; The water area is saturated, and there is almost no data available. Therefore, we can only use the unsaturated land wide-band algorithm to invert Chla; finally, there is currently no reliable atmospheric correction method to help MODIS obtain the Rrs data of inland turbid lakes (full and accurate atmospherically corrected data)

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