Study On Ecological Environment Quality Evaluation Of Main Urban Area And Closed Mining Area In Chongqing

The period of the 14 th Five-Year Plan is an important opportunity period for the high-quality development of regional social economy and ecological environment.With the rapid development of social economy,the ecological environment needs to be paid great attention to.Chongqing as a typical mountain city in southwest China,is the southwest development of social economy and ecological environment quality representative area,chongqing urban area is an important area of reflect the whole ecological environmental quality in chongqing,the main mine pit of widely distributed in the area of the negative effect on the ecological environment did not end because of closed mines.Therefore,it is of great significance to grasp the change of ecological environment quality in the main urban area and the closed pit mining areas in Chongqing.In this paper,the ecological environment quality evaluation system of the main city area and the closed pit mining area in Chongqing is constructed by using the comprehensive index method.Based on remote sensing image data and other relevant statistical data,this paper analyzed the spatiotemporal trends of land use and vegetation cover of major ecological indicators in Chongqing.Based on the established evaluation index system,the quantitative evaluation results of ecological environment quality in the main urban area and mining areas of Chongqing were obtained,and the correlation was compared with the evaluation results of remote sensing ecological index RSEI.The main conclusions are as follows:(1)The land use types in the main urban area of Chongqing have been transformed to different degrees from 2000 to 2020,and the dynamic change range of land use types is large.During the past 20 years,a large amount of arable land was mainly converted to construction land,and the area of forest and grass land remained at a stable level.The change range of land use landscape index is small,and the land landscape types are rich,but the overall land landscape pattern in the main city area is scattered and broken.(2)From 2000 to 2020,the monthly NDVI mean,surface precipitation and average air temperature of five years in Chongqing showed an obvious change characteristics,which first increased and then decreased.The monthly mean of NDVI from July to September in each year was relatively high,while the monthly mean of NDVI from January to March was relatively low.The monthly NDVI mean has a high positive correlation with the average temperature,and the variation range of precipitation within the same NDVI monthly mean is large(3)From 2000 to 2020,the comprehensive index CJ of ecological and environmental quality in the main urban area and the pit closure mining area of Chongqing decreased first and then increased,and the ecological and environmental quality showed a gradually improving trend.The CJ in the main urban area decreased from 0.4914 in 2000 to the lowest 0.3663 in 2005 and then increased to 0.5673 in2020.The CJ of mining area decreased from 0.6034 in 2000 to 0.4214 in 2010 and then increased to 0.5673 in 2020.(4)From 2000 to 2020,the remote sensing ecological index RSEI of the main urban area and the closed mine area in Chongqing decreased first and then increased,and the ecological environment quality showed a gradual improving trend.Remote sensing ecological index RSEI in the main urban area increased from 0.514 in 2005 to0.715 in 2020.The remote sensing ecological index RSEI in the mining area decreased to the lowest value of 0.501 in 2010 and rose to 0.616 in 2020.(5)The evaluation results of ecological environment quality of Chongqing main urban area and mine closure area obtained by the two evaluation methods have strong correlation,and the change trend of ecological environment quality is roughly the same.The correlation coefficient between the main city CJ and the main city RSEI is0.8492,indicating a strong correlation,and the correlation coefficient between the mining area CJ and the mining area RSEI is 0.9548,indicating a strong correlation.The results of the two methods of ecological environmental quality assessment showed a trend of improvement.