【摘要】 基于遥感和地理信息系统技术,利用1998—2008年SPOT-VEGETATION归一化植被指数(NDVI)数据对塔里木河干流区1998—2007年植被覆盖的时空变化进行了监测,并从气候变化和土地利用变化双重角度分析了植被覆盖变化的原因。研究表明,塔里木河干流区植被覆盖变化经历了两个阶段:1998—2001年植被覆盖严重退化时期;2002—2007年植被覆盖度由急剧上升到缓慢下降再到持续升高时期,NDVI明显高于20世纪末期水平。塔里木河干流区植被覆盖变化存在显著的空间差异,绿洲农业灌溉区和退耕还林还草生态恢复区的植被覆盖度显著提高,天然草地植被区的植被退化严重。塔里木河干流区植被覆盖变化是气候和土地利用变化共同作用的结果。温度对植被覆盖变化的影响表现为对植被生长年内韵律的控制和秋季植被生长期的延长,年降水量的波动式上升是导致塔里木河干流区植被覆盖变化两个阶段呈现差异的主导因素。更多还原

【Abstract】 The RS and GIS technology were used to monitor the spatial and temporal variations of vegetation cover along the main stream of the Tarim River during the period of 1998—2008 based on the Normalized Difference Vegetation Index(NDVI)data of SPOT-VEGETATION with 1 km×1 km spatial resolution.The relationship between vegetation cover change and climate and land use change was analyzed.The results are as follows.The change of vegetation cover experienced two various periods:the vegetation degradation period during 1998—2001,when vegetation cover improved with fluctuations from2002 to 2007;the vegetation restoration period from2002 to 2007,and the NDVI level in 2007 was obviously higher than that at the end of the 21 century.There was a significant difference of the vegetation cover change between oasis and desert grassland.The vegetation cover in oasis agricultural irrigation area and ecological restoration zone improved significantly,but the NDVI of desert forest and grassland decreased severely.The change of vegetation cover was the result of interaction of climate change and land use change.The influence of temperature on vegetation cover change is presented as controlling the rule of annual vegetation growth and prolonging the growth period of vegetation.The increase of annual precipitation was the dominant factor of vegetation cover improvement.Excessive reclamation and overgrazing were the reasons of cultivated land increasing and grassland degradation,respectively.更多还原