Research On Water Quality Remote Sensing Monitoring Method In Water Function Zoning Of Xinyang City Based On Adaptive Minimum Distance Classification

Water pollution has become a severe problem under the situation of rapid economy development and industrialization.The study of water quality monitoring requires large amounts of data as support.Usually,monitoring is a manual work by collecting and analyzing samples from sampling zones.This kind of work can give us accurate data of water quality,but it will take a huge amount of resources such as time and labor.So it cannot achieve large-scale,real-time monitoring.Remote Sensing water quality monitoring has the advantages of low cost,wide range,and easy for long-term dynamic monitoring.This paper took the water functional zones of Xinyang City as research areas,collected and analyzed the water quality from 64 sections in the water functional zones,and made an assessment according to the comprehensive index of organic pollutants.A water area extraction optimization method based on vector area was proposed to optimize the water extraction results among the four water indexes of MNDWI,NDTBI,AWEI,and RNDWI.Based on the measured data of the monitoring section and the image data of the Landsat-8 remote sensing monitoring,a water quality inversion model based on the adaptive minimum distance classification method was established.This mode can be applied to the water quality monitoring in the water functional zones of Xinyang City.The main research results are as follows:(1)Through the analysis of the extraction results of the complex terrain and water in the study area,the water samples of the study area were extracted.Using the four water indexes as methods(MNDWI,NDTBI,AWEI,and RNDWI),the extraction results were compared and analyzed.It was found that the NDTBI index can give a better water extraction from architectures and shadowed areas of hills,but the extraction results cannot completely eliminate the interference factors.So the water-body index optimization method based on area vector is researched and proposed.This method can effectively eliminate the interference factors such as the shading of the water body,the architectural features and river banks.(2)Based on the 64 water quality monitoring section in the research areas,the comprehensive index method was used to evaluate and classify the water quality,the spectral reflectance was analyzed,and the model of water quality grades and spectral reflectance was established.(3)With water quality grades-spectral reflectance model,a water quality inversion model was constructed to invert water quality grades in the water functional zones of Xinyang City,and achieved water quality monitoring in Xinyang City.The accuracy of water quality inversion model was verified by field measured water quality data.The water quality results of the water quality inversion model were consistent with the measured water quality by 92.33%.