陕北榆林地区沙漠化土地类型及时空变化分析

根据1987年和1999年两个时相TM遥感影像解译成果，运用地理信息系统空间分析方法及数理统计方法，分析了陕北榆林地区1987-1999年间土地沙漠化程度和土地沙漠化时空分布变化特征。并有所好转，这主要得益于当地政府对土地沙漠化的积极治理和有效政策，生态环境脆弱，气候干燥，多风是本区土地沙漠化的主要自然驱动因素，不合理的人类活动则是沙漠化的诱因，人为的积极治理措施可以有效控制沙漠化的进程。

Types and temporal-spatial change of desertized land in the Yulin area, northern Shaanxi

According to the results of TM remote sensing image interpretat io n of two time phases in1987and1999and using the space analysis and ma thematic statistics of the geographic information system,the paper analyzes th e degree of land desertization and features of the temporal-spatial change of land desertiza-tion in the Yulin area,northern Shaanbei,in1987-199 9and discusses the cause of land desertization.The analytic results indicate that since the late1980s the process of the land desertization of the area as a whole has tended to be stable and taken a more or less favorable turn.Th is mainly benefits from the policies of active and effective control of land desertization implemented by the local government.The fragile ecologi-cal envi ronment ,arid climate and plenty of wind are main natural driving factors for land desertization,while irrational human activities are a factor of inducin g land desertization.Measures of active control and improvement can effectiv ely control the process of desertization.