| The daily life of mankind is inseparable from the use of water resources,and it is also the basis for the continued development of society.However,with the rapid development of modern society and people’s uncontrolled use,the pollution of the aquatic ecological environment around the world has become more and more serious.Conventional water quality monitoring methods are time-consuming and labor-intensive,and the use of remote sensing technology to monitor water quality has unique advantages such as speed,accuracy,and periodicity,and has been widely used in daily water environment quality monitoring.Ring River is located in the downtown area of Hefei City.Although water quality control has been carried out in recent years,the overall water quality is still poor,exceeding the surface V water standard.In this paper,by combining the measured water quality parameter data and Landsat-8 satellite image data,a remote sensing inversion model of the water quality parameters of the Ring River is established to provide a basis for water quality monitoring of the Ring River and early warning and prevention of eutrophication.This paper takes the water body of Ring River as the research object,uses the measured water quality parameter data and Landsat-8 satellite image data to establish a remote sensing inversion model of the water quality parameter of Ring River,and uses the obtained inversion model to predict the water quality parameter The eutrophication level of the water body of Ring River was analyzed and evaluated.The research content includes: determination of water quality parameters of collected water samples;correlation analysis between band values and measured water quality parameters in spss software to obtain the most suitable single band and band combination;the use of the most suitable single band,band combination and actual measurement Regression analysis of the water quality parameters to obtain the inversion model,analysis and verification of the accuracy of the two inversion models,select the most suitable water quality parameter model.The corresponding inversion model was used to invert the chemical oxygen demand,total phosphorus,total nitrogen,and chlorophyll a concentration of the water body of the Ring River,and the data obtained from the inversion were used to evaluate the eutrophication of the water body of the Huancheng River.The research results of this article are as follows:(1)By analyzing the correlation between the band value and the measured water quality parameter data,the single band and band combination with the highest correlationwith chemical oxygen demand are B5 and(B2-B5),respectively.and the single-band and band combination with the highest correlation with total phosphorus are B5 and(B2-B5),respectively.The single band and band combination with the highest nitrogen correlation are B6 and(B1-B6),respectively,and the single band and band combination with the highest correlation with chlorophyll a are B5,(B6-B7)/(B6 + B7),respectively.(2)Select the single band and band combination values as independent variables,and the chemical oxygen demand,total phosphorus,total nitrogen,and chlorophyll a concentration values as dependent variables for regression analysis to establish linear,logarithmic,quadratic,cubic,power,exponent Inversion model.The accuracy analysis of the established single-band and band combination inversion model shows that the overall accuracy of the band combination inversion model is higher,and select the most suitable water quality parameter inversion model from it,and apply it to the satellite image data on April 13,2019.The correlation coefficient between the predicted value and the measured value in the combined model of chemical oxygen demand band inversion model is 0.7006,the correlation coefficient between the predicted value and the measured value in the total phosphorus band inversion model is 0.9028,and the chlorophyll a band combined inversion model The correlation coefficient between the predicted value and the measured value is 0.7053.Due to the insufficient optical properties of total nitrogen,a suitable inversion model cannot be established in this study.(3)Using the three water quality parameter inversion models of chemical oxygen demand,total phosphorus,and chlorophyll a combined with satellite image data,the water quality parameter concentration of the Ring River from 2018 to 2019 is inversed,and the interannual changes of water quality parameters are analyzed.According to the analysis,the concentration of chemical oxygen demand,total phosphorus and chlorophyll a in the northern section of the ring-shaped city is higher than that in the southern section.The chemical oxygen demand concentration varies seasonally as follows: when the overall temperature is higher in summer,the chemical oxygen demand concentration is higher;as the temperature drops into autumn and winter,the chemical oxygen demand concentration will decrease accordingly.The concentration of total phosphorus is slightly higher in spring and autumn,and the concentration will be relatively lower in summer and winter.Chlorophyll a concentration changes with seasonality: summer> autumn> spring> winter.(4)According to the above three water quality parameter inversion models combined with satellite image data,the water quality of the water body of the Ring River from 2018 to 2019 is inversed and the eutrophication is evaluated.According to the analysis of thecomprehensive nutritional status index method and scoring method,it is concluded that the eutrophication degree of the water body of Ring River is already high.And the degree of eutrophication in the north section of the city is higher than that in the south section.The eutrophication degree changes with the seasons.In the summer and autumn with higher temperature,the eutrophication degree has a tendency to increase.As the temperature decreases into the winter,the eutrophication degree will have a tendency to decrease.Figure [33] table [39] reference [84]. |
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