Inversion Of Water Quality Elements In Small And Micro Size Water Region Using Multispectral Image By UAV

The traditional water quality remote sensing adopts satellite remote sensing method and is limited by the resolution of satellite remote sensing images.It is currently used for water quality monitoring in large-area waters.For the spatial distribution of water quality parameters in small and micro waters,a new method is needed to solve it.In recent years,with the continuous expansion of the application fields of UAVs,UAV remote sensing technology has become a new direction of water quality remote sensing research due to its flexible data acquisition and high resolution.The total phosphorus(TP),suspended sediments concentration(SS)and turbidity(TUB),these three parameters all have certain value for the overall estimation of water quality,and have achieved certain results in the previous water quality factors inversion study.The paper uses the Donghu Lake of Zhejiang Agriculture and Forestry University as the research object,uses the Mica Sense Red Edge to acquire multi-spectral images,extracts 16 spectral parameters,and constructs the inversion models of TP,SS and TUB in the Donghu Lake waters.By comparison,the following optimal models of water quality elements are obtained: the exponential function model(ETP16)and the polynomial model(PLTP16)fitted with the spectral parameter V16,and the determination coefficient R2 are 0.7897 and 0.7965,respectively,the polynomial model(PLSS5)and the unary linear function model(USS8),which are fitted to the spectral parameters V5 and V8,respectively,and the coefficient R2 are 0.7503 and 0.7866,respectively.and the linear function model(UTUB4)and polynomial model(PLTUB4)fitted by the TUB and the spectral parameter V4,and the coefficient R2 are 0.6083.and 0.7334.The results show that the overall accuracy of the UAV inversion model is high,which can accurately estimate the TP,SS and TUB.The paper further extends TP's exponential function model(ETP16)and polynomial model(PLTP16),SS polynomial model(PLSS5)and unary linear function model(USS8),and TUB's unary linear function model(UTUB4)and polynomial model(PLTUB4).The multi-spectral images of the Donghu Lake region were respectively applied to obtain the spatial distribution map of the concentration of TP,SS and TUB in the Donghu Lake.Finally,based on the actual situation of the study area,this paper objectively analyzes the concentration changes of three water quality parameters: total phosphorus(TP),suspended sediments concentration(SS)and turbidity(TUB)in the Donghu Lake.The monitoring of urban water quality by UAV identifies new sources of data and technical means that provide a reliable basis for water environment protection and governance.