基于RSEI模型的兰西城市群生态环境质量的时空格局及动态分析

Temporal and spatial pattern and dynamic analysis of eco-environmental quality of Lanzhou-Xining urban agglomeration based on RSEI model

兰西城市群的生态地位突出,探究兰西城市群生态环境的时空格局和动态趋势,对于生态环境的保护具有重要的意义.借助Google Earth Engine(GEE)遥感云计算平台,调用Landsat影像计算了绿度、湿度、热度和干度指标,通过主成分分析法完成了遥感生态指数RSEI(Remote Sensing Ecological Index)的构建,并且采用地理探测器分析了生态环境质量变化的驱动因素.时空分析的结果表明:2010-2020年,兰西城市群的生态环境质量从时间上表现为持续改善,RSEI均值年均增长0.017,空间上呈现“西高东低”的现象;动态分析的结果表明:生态等级差和较差的面积逐年减少,而优、良、中等的面积逐年增加.2010-2015年和2015-2020年改善的面积占比分别为50.60%和40.27%,其中轻度改善的占比分别为49.93%和39.58%,轻度改善是生态环境向好发展的主导原因;驱动机制的研究表明降水量是影响生态环境质量变化的主导因素.研究表明,近10年,兰西城市群的生态环境持续改善,GEE平台能够及时的评估区域的生态环境质量.

Lanzhou-Xining urban agglomeration has a prominent ecological status and undertakes the great responsibility of ecological protection.How to timely and accurately evaluate the temporal and spatial pattern and dynamic trend of the ecological environment of Lanzhou-Xining urban agglomeration is of great significance for the protection of the ecological environment.With the help of Google Earth engine(GEE)remote sensing cloud computing platform,this paper calls Landsat images to calculate the indexes of greenness,humidity,heat and dryness.he remote sensing ecological model is completed by principal component analysis(RSEI),and the drivers of ecologicalquality change were analyzed using Geodetector.The results show that from 2010 to 2020,the average annual growth of RSEI was 0.017/a,showing the phenomenon of high in the West and low in the East.The areas with poor ecological grade and poor ecological grade decreased year by year,while the areas with excellent,good and medium ecological grade increased year by year.From 2010 to 2015 and From 2015 to 2020,the improved areas accounted for 50.60%and 40.27%respectively,of which the slightly improved areas accounted for 49.93%and 39.58%respectively.The slight improvement is the leading reason for the good development of the ecological environment.Studies on the driving mechanisms indicate that precipitation is the dominant factor influencing changes in ecosystem quality.The results show that the ecological environment of Lanzhou-Xining urban agglomeration has developed well in recent 10 years.By the using GEE platform,the temporal and spatial pattern of ecological environment quality in the Lanzhou-Xining urban agglomeration can be obtained in time and accurately.