Study On Ecological Environment Quality Evaluation Of Shiyang River Basin Based On RSEI Index

Human material civilization and spiritual civilization is based on the resource consumption speed is greater than the load capacity of the price,the price of this kind of resource consumption and consumption rate will bring the earth ecological environment for human survival a big threat,and it also exacerbate indirect contradiction between human and nature,and further lead to the direct contradiction between human and society.Ecological environment refers to the ecological functional unit composed of living and non-living things within a certain space through material circulation,energy flow and their interactions.The quality of ecological environment has a profound impact on global change and regional sustainable development.At present,most of the research on ecological environment quality in China is concentrated in the large cities in the east and south,and the research on the arid areas in northwest China is relatively lack,especially the research based on remote sensing data is very few.Shiyang river basin,including the four major geomorphic unit,hilly land and desert of northern,respectively,in the central plains corridor,and the south qilian mountain,the south qilian mountain to become national nature reserve as early as 1988,these unique geomorphic environment make the basin ecological environment quality present a special local characteristics different from big cities.As an economically prosperous area in the inland river basin west of the river,the dynamic change of ecological environment quality and how to evaluate the impact on the river basin are scientific issues worth discussing.In shiyang river basin as the research object,this paper selected in 1992,1998,2004,2010,2016 and 2017,six Landsat satellite images as the research data,using new Remote Sensing Ecological Index RSEI(Remote Sensing-based Ecological Index,RSEI)combined with other data analysis and evaluation of shiyang river basin Ecological environmental quality from 1992 to 2017,and the district/county RSEI Index value hierarchy and change in classification,Then the causes of the change of ecological environment quality in shiyang river basin were analyzed.The main conclusions of this paper are as follows:(1)In recent 26 years,the ecological environment quality of shiyang river basin has shown a trend of first rising,then declining and then rising.The RSEI indexes in1992,1998,2004,2010,2016 and 2017 were 0.4736,0.4808,0.4942,0.5353,0.4806 and 0.5558,respectively.The index contains four indexes,namely,greenness,humidity,dryness and heat.The research results show that these four indexes have a great influence on shiyang river basin,especially greenness and humidity have the largest influence,followed by heat and dryness.Generally speaking,the ecological environment quality of the research area has been developing in a good direction in the past 26 years.(2)on the whole,from 1992 to 2017,the ecological environment quality of the basin presented a three-step stepwise distribution of "good in the south,stable in the middle and poor in the north",and the third step in the north gradually developed into the second step.After 2010,the change is more obvious in the north and parts of the east.By 2017,the region with a good rating covered almost all of the central and southeastern parts of the country.(3)the analysis of the ecological environment quality of each district/county in shiyang river basin shows that the ecological environment quality of tianzhu county and sunan county has been kept in a good state,ranking the first and the second among the districts/counties in shiyang river basin.Jinchuan district and yongchang county have been in a relatively poor state of ecological environment quality in shiyang river basin,ranking 5th and 6th overall,and minqin county is the worst,ranking 7th.According to the change level of RSEI index in all districts and counties in the past 26 years,the ecological environment in all districts and counties in shiyang river basin has been improved,and the overall ecological environment quality is at "good" level.(4)From the cause analysis,the factors that affect the change of ecological environment quality include natural factors and human factors.The correlation analysis shows that meteorological factors have different degrees of influence on the ecological environment quality of the upper reaches,middle reaches and lower reaches of shiyang river basin.Meteorological factors have a small impact on theenvironmental quality of the middle reaches,while the meteorological factors affecting the downstream ecological environmental quality include average temperature,minimum temperature and evapotranspiration,while relative humidity has a significant negative correlation with the downstream ecological environmental quality.Through principal component analysis of social and economic factors in the study area,it is found that GDP,three industries and non-agricultural population in the study area are the main driving factors affecting the ecological environment quality of shiyang river basin.