内蒙古中部地区土地荒漠化遥感调查及环境质量评价

The Desertification Study and Environmental Quality Assessment in Middle Inner Mongolia Region

选择内蒙古中部地区作为典型荒漠化区域,根据荒漠化土地分类体系,确定决策树的结构以及各类地物在树形中的位置。基于各类地物的光谱反射特性和图像数据反映的综合特征,采取相应的识别和提取方法,以最大限度地利用遥感数据源。在研究过程中,采用从多光谱及多时相TM和ETM+遥感数据中提取出的光谱反射特性、土壤调节植被指数、土壤亮度指数以及土壤湿度指数等复合指数进行不同地物的分类和提取。结果表明:利用决策树分层提取法可以有效地排除和避免提取地物时多余信息的干扰及影响,目标明确。然后,通过图像代数检测法及目视解译法确定1990—2000年土地荒漠化的变化信息,对内蒙古中部地区的荒漠化演变规律做出分析。最后,结合研究区气候数据,在G IS支持下,通过对研究区生态环境质量变化和气候因子变化的相关性分析,表明研究区影响环境变化的主要因子是降水量与蒸发量(干燥度)。

This paper is about Middle Inner Mongolia region, which is a typical region of desertification. The structure of the decision tree and the corresponding position of each target are determined according to the desertification land classification. According to the spectrum-reflecting characteristic of targets and the integrated feature of TM and ETM ＋ image data, proper identifying and extracting methods are applied. So the potential of the remote sensing data is maximized. From the multi-band and multi-time TM and ETM^＋ remote sensing data, the spectrum-reflecting properties, the Soil-Adjusted Vegetation Index（SAVI）, Soil Brightness Index（TC1）, and Moisture Index（MI） are extracted. And these indexes are used to distinguish and classify the different land types. The result shows the decision tree and multi-layer method is efficient to decrease the intrusion of the extra information in the pixel identification and make the targets definite. Through Image Algebra Detection method and Visual Interpretation method, the changes of the desertification from 1990 to 2000 are collected, and the evolvement rule of desertification in the study area is analyzed. Finally, with the technology of GIS, the analysis of the ecological environment quality changes and climate factors changes reveals that the main factors to influence the environmental changes are precipitation and evaporation（desiccation）.