基于GEE的长三角生态环境质量评价及其影响因素分析

Ecological Environment Quality Assessment and Its Influencing Factors in Yangtze River Delta Based on GEE

把握区域生态环境的时空格局,厘清其主要影响因素,对实现区域生态文明建设具有决定性作用。基于GEE平台,构建遥感生态指数(RSEI),解析2001—2020年间长三角生态环境质量时空变化,并利用随机森林模型分析其影响因素。结果显示:(1)时间维度上,RSEI先降后升,但研究期末仍低于期初;空间维度上,山地丘陵区RSEI显著高于各城市建成区。(2)时空演化上,皖北地区RSEI始终呈上升态势,长江沿岸及太湖周边城市建成区RSEI明显呈下降趋势。(3)建设用地面积占比(POCL)、坡度(SLOPE)和高程(DEM)是影响长三角RSEI的主导因素。当POCL大于3%时,对RSEI起抑制作用,在3%-50%区间,其抑制作用更为显著;SLOPE在0-0.6°和2.5°-29.5°区间对RSEI起促进作用,而在0.6°-2.5°和大于29.5°区间对RSEI起抑制作用;DEM≥1150 m时,其对RSEI的促进作用达到最大后保持平稳。进一步优化城市用地空间布局,增加城市绿地面积,是实现长三角高质量发展的必由之路。

Grasping the spatial and temporal pattern of the regional ecological environment and clarifying its main influencing factors have a decisive role in realizing the construction of regional ecological civilization.Based on Google Earth Engine platform,we analyzed the temporal and spatial characteristics of ecological environment quality in Yangtze River Delta from 2001 to 2020 by constructing Remote Sensing Ecological Index(RSEI),and discussed the influencing factors by random forest method.The results are as follows:(1)In the temporal dimension,RSEI decreased first and then increased,but it was still lower at the end of the study than at the beginning of the study.(2)In terms of spatio-temporal evolution,RSEI in northern Anhui was always on the rise,while RSEI in built-up areas along the Yangtze River and around Taihu Lake was obviously on the decline.(3)Construction land area proportion(POCL),SLOPE and elevation(DEM)are the dominant factors affecting RSEI in the Yangtze River Delta.When POCL is greater than 3%,it has an inhibitory effect on RSEI,and the inhibitory effect is more significant in the range of 3%-50%.SLOPE promoted RSEI in the interval of 0°-0.6°and 2.5°-29.5°,and inhibited RSEI in the interval of 0.6°-2.5°and greater than 29.5°.When DEM≥1150 m,its promoting effect on RSEI reaches the maximum and remains stable.To further optimize the spatial layout of urban land and increase the area of urban green space is the only way to achieve high-quality development of the Yangtze River Delta.