Study On The Effectiveness Evaluation Method Of Satellite Remote Sensing In The Monitoring Of Lake And Reservoir Water Quality

With the development of economy and society,the pollution risks facing waters are increasing,and water quality monitoring and protection treatment become particularly important.Traditional ground manual monitoring and online monitoring cannot meet the long-term and large-area information needs of water environmental protection and governance.Remote sensing technology can overcome the shortcomings of traditional monitoring methods and realize large-scale dynamic monitoring of the water environment.However,most of the current quantitative remote sensing modeling methods of water quality are combined with surface water quality monitoring data,and almost all waters need to be modeled separately,and the model portability is poor.Remote sensing water color index is an index describing the color of waters,which can reflect the pollution and eutrophication of waters.Although it cannot quantitatively correspond to the water quality parameter value,it can be calculated without relying on ground monitoring data,and it occupies a wide range of water quality monitoring and early warning applications Certain advantages.In this paper,based on the principle of water quality remote sensing monitoring and the spectral characteristics of the waters,the FUI index of the waters is calculated using the multi-temporal GF-1 WFV data,and the reference index CI is used to modify the consistency of the FUI of different time phases to construct the FUI time series;And the synchronized surface water quality online monitoring data,the effectiveness evaluation index of water quality remote sensing monitoring is constructed,and the effectiveness of the remote sensing monitoring of water quality is evaluated from the aspects of the significance of the FUI change of the waters and the synchronization of the FUI change and the surface water quality online monitoring data.Taking 17 lake and reservoir water sources in Shandong Province as the research object,the remote sensing images and surface water quality online monitoring data from March to October 2018 were collected,and the method was applied to determine the remote sensing of the water quality of 17 lake and reservoir water sources.The effectiveness of monitoring and analysis of the changes in water quality in 2018.The main conclusions are as follows:(1)Remote sensing water quality monitoring is not effective for all waters.Its availability depends on whether changes in water quality can cause changes in water color.Traditional remote sensing water quality modeling methods usually require the cooperation of surface water quality monitoring data,and the rate of individual waters modeling.It 's hard to meet the needs of fast judgment on a large scale.The remote sensing water color index can be obtained independently from the surface water quality monitoring data,and can be obtained by using the remote sensing data independently.It has the convenience of large-scale rapid calculation and can be used as a reference indicator for the judgment of the availability of remote sensing water quality monitoring.(2)Affected by factors such as the intensity of sunlight,the water color index of different time phases needs to be corrected for consistency when performing time series changes.In this paper,a CI color index correction method based on unchanged color buildings is constructed,which uses relatively unchanged buildings around the water body to correct the FUI of waters at different time phases to form a remote sensing water color time series,which can be used to compare the changes of water color at different times.analysis.(3)Based on the principle that the change of water color is determined by the change of the concentration of the substance in the water,this paper constructs the evaluation index and calculation method of the effectiveness of remote sensing water quality monitoring by using the synchronization of water color index and water quality online monitoring data.By using this method,17 water source reservoirs in Shandong Province are distinguished,and it is found that the remote sensing of Andi reservoir,Gaoya reservoir and Jindou reservoir can not monitor the water quality;Chanzhi reservoir,Jihongtan reservoir,Menlou reservoir,Mushan reservoir,Muyu reservoir,Queshan reservoir,Rizhao reservoir,Tieshan reservoir,Wangwu reservoir,Wohushan reservoir,Xiashan reservoir and Yeyuan reservoir,etc can be effectively monitored by remote sensing;while Jinxiuchuan Reservoir and Yinfu Reservoir remote sensing has uncertainties in its monitoring.In areas where remote sensing is available,the three-dimensional monitoring network and layout can reduce the layout of ground stations and the density of ground stations.For areas where remote sensing is unavailable,it is necessary to strengthen the layout of ground monitoring.(4)Analyze the spatial and temporal changes of the water quality of remotely monitored reservoirs by using the image difference method and the linear regression method.The water quality of Mushan Reservoir is better in June,July and October,and the water quality in May and August is worse;the water quality of Queshan Reservoir is better in July,the water quality in June is more stable,and the water quality in April,May and October is worse;The water quality of Rizhao Reservoir is better in April and September,and the water quality in June and October is worse;the water quality of Wohushan Reservoir is worse in April and May,the water quality is better in October,and the water quality in June is more stable;The water quality is better in October and October,the water quality in August is worse,and the water quality in September is more stable.In terms of overall spatial distribution,the water quality of Mushan Reservoir,Queshan Reservoir,Rizhao Reservoir and Bathing Reservoir has improved significantly,while the water quality of Wohushan Reservoir and Xiashan Reservoir has significantly deteriorated.