区域生态环境变化的遥感评价指数

基于遥感信息技术提出一个新型的遥感生态指数(RSEI),以快速监测与评价区域生态质量.该指数耦合了植被指数、湿度分量、地表温度和土壤指数等4个评价指标,分别代表了绿度、湿度、热度和干度等4大生态要素.与常用的多指标加权集成法不同的是,本研究提出用主成分变换来集成各个指标,各指标对RSEI的影响是根据其数据本身的性质来决定,而不是由人为的加权来决定.因此,指标的集成更为客观合理.将RSEI应用于福建长汀水土流失区,并与国家环境保护部《生态环境状况评价技术规范》中的生态指数EI的计算结果相比较,发现二者的结果具有可比性.不同的是,RSEI不仅可以作为一个量化指标,而且还可以对区域生态环境变化进行可视化、时空分析、建模和预测.因此,可弥补EI指数在这些方面的不足.

A remote sensing index for assessment of regional ecological changes

A remote sensing based ecological index (RSEI) was developed specially for monitoring and assessing regional ecological changes. The index combined four indicators from existing remote-sensing indices/components to represent greenness, dryness, wetness and heat, which were the important ecological indicators frequently used in assessing regional ecology. Instead of a weighted addition of the four indicators, the principal component analysis (PCA) was utilized to compress the four indicators into one in order to assess overall regional ecological status. The RSEI was then constructed using the first component (PC1). The application of RSEI in Hetian area of County Changting in Fujian Province, China, showed that the RSEI could quantitatively reveal regional ecological changes during the period from 1988 to 2010. The RSEI values could be well compared with the commonly-used ecological index (EI). Nevertheless, besides working as a quantitative indicator, the RSEI had more functions than the EI, such as detecting, simulating and predicting spatiotemporal changes of regional ecological quality.