中文摘要：

基于AVHRR/NDVI和MODIS/NDVI遥感数据,通过拟合两种数据源延长NDVI时间序列来反演了三江并流河源区1982—2012年植被覆盖度空间格局的变化规律,并结合气温和降水量数据,从不同时空尺度上分析了植被覆盖变化趋势及其对气候变化的响应。结果表明：1.研究区植被覆盖度整体上随着热量梯度呈南高北低、东高西低的态势分布,且海拔在4 000 m以下的区域植被覆盖度较高,平均值在0.68~0.75;2.研究期间,植被覆盖度以0.02/（10 a）的变化率呈增加趋势,海拔在4 600 m左右和低覆盖度的区域植被增加趋势显著,显著增加区域面积占研究区总面积的36.4%,主要分布于沱沱河流域、怒江流域（除源头外）和研究区东南部等地区,这些区域植被覆盖度平均值仅为0.36;3.相对于降水量,研究区的植被覆盖度与气温要素相关性更为显著,特别是高原面上的植被覆盖度整体上与气温呈显著正相关关系,显示了强烈的热量限制性生态类型的特点。

英文摘要：

The spatial pattern and trend of vegetation coverage during the period 1982—2012 in the source regions where three rivers flowing parallelly（ Three Parallel Rivers region） are obtained and discussed based on the normalized difference vegetation index（ NDVI） data from Advanced Very High Resolution Radiometer（ AVHRR） and Moderate Resolution Imaging Spectroradiometer（ MODIS）. Combined with the temperature and precipitation data,the responses of vegetation cover to the climate change are also presented. The results showed that： 1） The spatial distribution of vegetation coverage were higher in the south and east,and lower in the north and west along with the spatial pattern of heat in Three Parallel Rivers region,and it was higher below the altitude of 4 000 m in the region.2） During the study period,the vegetation coverage presented an increasing trend with a rate of 0. 002 /（ 10 a） in Three Parallel Rivers region. Areas with altitude about 4 600 m or low vegetation coverage showed obvious increase trend. The area with significant increase trend occupies 36. 4% of the study area and mainly distributes in Tuotuo River basin,Nujiang basin（ except the area of headwater） and the southeast of the study area. 3） Vegetation coverage in the study area has a more significant correlation with temperature compared with precipitation. In particular,vegetation coverage on plateau showed a significantly positive correlation with temperature,which exhibited a strong thermal limitation.