皖江城市带近20 a生态环境变化遥感指数分析

随着城市化进程的不断加快，环境保护问题越来越突出，加强生态文明建设也越来越成为城市发展的重心之一，因此快速监测城市生态环境变化显得尤为重要。选取1995年、2005年、2015年Landsat TM/OLI影像为主要数据源，分别提取绿度、湿度、干度、热度4个生态因子作为评估指标，结合主成分分析，生成遥感生态指数（RSEI）,客观、迅速、定量地对皖江城市带近20 a生态环境变化进行分析。结果表明：1995~2015年皖江城市带生态环境质量先降后升，总体呈上升趋势。其中RSEI从1995年的0.710下降至2005年的0.683再升至2015年的0.728，总共上升了2.54%；1995~2015年生态环境恶化区域面积比例由20.03%到14.56%，减少了26.86%；生态环境改善区域面积比例由21.87%到29.39%，增加了34.39%。生态环境恶化区域主要集中在长江沿岸经济发达的扩张型城市和地区；生态环境改善区域主要集中在植被覆盖、注重环境整治、绿化效果显著地区。总的来说，城市生态质量与植被覆盖情况（NDVI）和不透水建筑面积（NDBSI）关系最为密切，城市扩张发展的同时，应该加强生态文明建设，注重环境保护，增加绿化面积，实现城市的可持续发展。 关键词： 皖江城市带；RSEI指数；城市生态；变化检测；主成分分析

Remote Sensing Index Analysis on Ecological Environment Changes in the Recent 20 Years of City Belt in Wanjiang

With the accelerating process of urbanization, the problem of environmental protection is becoming more and more prominent. Strengthening the construction of ecological civilization has increasingly become the focus of urban development. Therefore, it is particularly important for rapid monitoring of changes in urban ecological environment. Landsat TM/OLI remote sensing images of 1995, 2005 and 2015 were chosen as the main source of data. Four ecological factors were calculated as evaluation indicators, namely greenness, wetness, dryness, and heat. Principal component analysis was used to derive the remote sensing ecological index (RSEI). The ecological changes in Wanjiang city belt in recent 20 years were analyzed objectively, rapidly and quantitatively. The results show that the changes of ecological environment quality in Wanjiang city belt in 1995-2015 years are"down then up", with an overall rising trend. The RSEI dropped from 0.710 in 1995 to 0.683 in 2005, and then rose to 0.728 in 2015 with a total increase of 2.54％. During 1995-2015, the proportion of ecologically deteriorated areas decreased from 20.03％ to 14.65％, with a decrease of 26.86％. While the proportion of ecologically improved areas increased from 21.87％ to 29.39％, with an increase of 34.39％. The ecologically deteriorated areas are mainly concentrated in the expanding cities and regions along the Yangtze River. The areas with improved ecological environment mainly concentrate on the areas with vegetation cover, environmental regulation and greening effect. Overall, urban ecological quality is most closely related to vegetation cover (NDVI) and impervious building area (NDBSI). With the development of urban expansion, we should strengthen the construction of ecological civilization, pay attention to environmental protection, increase the afforested area and realize the sustainable development of the city.