中国西南山地城市生态环境质量长时序变化及其评价——以重庆市为例

Long-term changes and evaluation of eco-environmental quality in mountainous cities in southwest China-Take Chongqing Municipality as an example

为研究中国西南地区山地城市的生态环境质量,选择以重庆市为例,利用遥感技术和Google Earth Engine(GEE)平台,构建遥感生态指数(RSEI,remote sensing ecological index),评价重庆市2000年~2021年的生态环境质量及其长时序变化。为探讨山地城市生态环境质量的主要影响因素,选取海拔、坡度、气温和降水四个影响因子,得到RSEI的海拔依赖性与坡度依赖性以及RSEI与气候因子的响应关系。结果表明:①遥感生态指数RSEI总体呈上升趋势,生态质量为“优”的面积增加了130.27%,生态质量为“差”的面积减少了65.68%,生态环境有明显的改善;②从RSEI随海拔、坡度变化曲线可以看出,0 m~1800 m范围内RSEI缓慢增加,1800 m~2800 m范围内开始减小,RSEI随坡度增加而增长,坡度>40°之后RSEI趋于平稳;③从RSEI与气候因子的响应曲线可以看出,温度和RSEI呈负相关,温度越高,RSEI越低;随着降水的增加,RSEI指数逐渐上升。研究表明,使用GEE平台可以对多云雾、植被覆盖度高的西南山地城市的生态环境质量进行长时序的监测和评价。研究结果可为中国西南地区山地城市的生态环境保护提供精细化管理,从而根据区域特色进行环境治理,实现生态环境与经济的协调发展。

In order to study the eco-environmental quality of mountainous cities in southwest China,this paper takes Chongqing as an example and uses remote sensing technology and the Google Earth Engine(GEE)platform to construct RSEI(remote sensing ecological index),and evaluates the eco-environmental quality and its spatial-temporal heterogeneity during 2000-2021 in Chongqing.In order to explore the main influencing factors of eco-environmental quality in mountainous cities,four influencing factors,namely elevation,slope,temperature,and precipitation,were selected to obtain the allocation-dependence and slope dependence of RSEI and the response relationship between RSEI and climate factors.The results show that:①The remote sensing ecological index RSEI showed an overall upward trend,and the area with"excellent"ecological quality increased by 130.27%,while the area with"poor"ecological quality decreased by 65.68%.The ecological environment improved,obviously,but there were still regional differences.Low RSEI pixels were mainly distributed in urban areas and showed an expanding trend in urban agglomeration.②It can be seen from the change curve of RSEI with altitude that RSEI increases with the increase of altitude from 2010 to 2021.Overall,RSEI increases slowly within the range of 0~1800m and begins to decrease within the range of 1800 m~2800 m.Similarly,RSEI increases with the slope increase.RSEI leveled off when the slope was greater than 40°.③According to the response curve of RSEI and climate factors,temperature and RSEI are negatively correlated,and the higher the temperature,the lower the RSEI;With the increase of precipitation,RSEI index increased gradually.The research shows that the ecological environment quality of Chongqing has improved significantly since 2000 with the development of urbanization and the effective management of the ecological environment.Remote sensing technology can be used to monitor and evaluate the ecological environment quality in the area with perennial cloudy coverage in a long time series,and provide a reference for the ecological environment protection of mountainous cities in southwest China.The results show that the GEE platform can be used to monitor and evaluate theecological environment quality in the southwest mountainous cities with cloud and high vegetation coverage.The ecological environment quality in Chongqing has improved significantly since 2000.The results of this study can provide exemplary management for the ecological environment protection of mountain cities in southwest China,carry out environmental management according to regional characteristics,and realize the coordinated development of the ecological environment and economy.