Study On Temporal And Spatial Variation Of The Ganjiang River Basin Water Remote Sensing Analysis

River is not only the main source of human fresh water resources,but also the key to maintain the ecosystem near the river basin.The Ganjiang River is the largest river in Jiangxi Province.Remote sensing research on time and space change of water body in the Ganjiang River Basin and revealing the variation types and water area of the Ganjiang River Basin,on the one hand can play a role in the monitoring of water resources and environment,provide the basis for the relevant departments to carry out comprehensive management of Ganjiang River;on the other hand,can also provide the basis for the development planning,and provide a basis for the quantitative inversion model of Ganjiang River water,has very important theoretical and practical significance.In this paper,the Ganjiang River Basin was taken as the study area,the 79 Landsat series satellite images and HJ satellite images for 22 years from 1995 to 2016 were preprocessed.According to the actual situation of the study area,the neural network method and model established by NDVI combined with NDWI was used to extract water from Landsat series satellite images and HJ satellite images?extraction accuracy is greater than 90%?,respectively.The analysis results of interannual and annual year changes of Ganjiang River Basin water area show that,in the 22 years,the Ganjiang River water area is increased in general,increased from710.794 km² of December 1995 to 1272.732 km² of December 2016;Among the 13 large reservoirs in Ganjiang River Basin,in addition to the Shangyou reservoir and the Sheshui reservoir,the area of the rest of the reservoir increased in varying degrees.This may be attributed to the relevant departments of the Ganjiang River new embankment,river beach protection and construction work wrecker hydropower station management and development,in particular,the reservoir area has a great influence on the reservoir area.Affected by the weather,the annual year change of the Ganjiang River water area has a lot of fluctuation.The comparative analysis of the annual year changes of 1995,2008 and 2016 show that in spring,the area of water area is increasing gradually.The months of the smallest area of water in the year have an early trend.These trends have a very important influence on the environment and ecology.On the basis of the analysis of the existing water body classification method and the extraction method of eutrophic water body,a classification model of water body suits for fhe Ganjiang River Basin was studied.The eutrophic water body was obtained by panicle cap transformation for Landsat series satellite images and setting up a corresponding threshold for its three components to get a eutrophic water body.Then,according to the characteristics of the image spectrum,the model of turbid water body is(b_red-b_green)/(?_red-?_green)>0 and the model of clear water body is(b_nir-b_red)/(?_nir-?_red)<(b_nir-b_green)/(?_nir-?_green),and the rest are light turbid water body.Water classification model of Ganjiang River Basin was established.The data of water quality monitoring site in the Ganjiang River Basin show that the extraction results have high accuracy.The analysis results of water type classification for the Ganjiang River Basin show that,the Ganjiang River Basin is relatively clear water.From the distribution of water types,the upstream water body is clearer than the downstream water body,and the water of the lake and reservoir is clearer than the river's water body.Eutrophication usually occurs in the surrounding lakes and reservoirs in the city from May to October.In the 22 years from 1995 to2016,the eutrophication water area of the Ganjiang River Basin was increasing,which should arouse the attention of the relevant departments to timely control the eutrophication water of the Ganjiang River Basin.