基于主成分分析的生态变化遥感监测——以宝鸡市城区为例

Dynamic monitoring of eco-environment quality changes based on PCA:A case study of urban area of Baoji City

利用遥感技术研究区域生态变化特征,具有实时、快速等优点。采用主成分分析法(principal component analysis,PCA),集成了绿度、湿度、干度和热度4个遥感指标,对2002—2013年间宝鸡市城区(陈仓区、金台区和渭滨区)及其土地利用类型的生态环境质量变化进行了综合评价。结果表明,2002—2013年间研究区生态环境质量等级提升的面积占研究区总面积的39.50%,等级下降的面积占10.96%,生态环境质量综合指数(synthetical ecological index,ESI)提升了0.31,近10 a来生态建设工作已取得显著成效;其中,陈仓区和渭滨区整体生态环境质量得到改善,ESI分别上升了0.38和0.23,而金台区有所下降,ESI降低了0.03;各土地利用类型ESI由高到低依次为林地、未利用地、草地、水域、耕地和建设用地,其中耕地生态环境质量相对稳定,林地、草地和未利用地得到改善,而水域和建设用地变差。

Using remote sensing method to study eco-environment quality changes is immediate and rapid. Based on remote sensing image and principle component analysis,the authors combined vegetation index,wet index,dryness index and temperature index to evaluate the eco-environment quality of Baoji City and the land-use types from 2002 to 2013. The results indicate that the ecological construction work has made remarkable achievements in the past 10 years. The area of improved eco-environment quality reached 39. 50%,while the area of degraded quality possessed only 10. 96%; in addition,synthetical ecological index( ESI) increased from 3. 25 to 3. 56. The eco-environment quality of Chencang District and Weibin District was improved while that of Jintai District was degraded. The ESI of land-use types from high to low is forest land,unexploited land,grassland,waters,cultivated land and construction land. RSEI degree of cultivated land has no significant change,that of forest land,grassland and unexploited land have been improved while water and construction land have been degraded.