中文摘要：

黄河源区是对环境变化敏感的重要冻土区,监测黄河源区内植被的动态变化,并分析其对相关环境影响因子的响应机制,对了解该区近年来冻土及水资源变化机理有着重要意义。基于2000—2010年的MOD44B植被盖度（Vegetation Continuous Field-MOD44B）产品对黄河源区内植被覆盖率的变化进行分段线性回归及趋势转折分析,从时间和空间角度揭示植被覆盖率的变化特征,探讨降水、坡度、高程等因素对植被覆盖率变化的影响,并选择主要影响因素建立模型对黄河源区内的植被覆盖率进行预测。结果表明：2000—2010年黄河源区内植被覆盖率呈现较强的纬度地带性,并在年际间表现出波动上升趋势;植被改善区域主要分布在扎陵湖和鄂陵湖以南地区,退化区域则主要分布在两湖以北,空间上存在明显的分界线;研究时间段的气温和降水均呈波动上升趋势,线性增长率分别为0.09℃·a^-1和8.9 mm·a^-1,整个区域内植被变化对于气温更加敏感。与植被改善区相比,植被退化区平均坡度和海拔更低,表明人类活动可能对植被退化产生了影响。

英文摘要：

The headwaters of the Yellow River is an important permaforst zone,and it is extremely sensitive to the environment change. It is crucial for understanding the underlying mechanism of the change of permafrost and water resources to monitor the dynamic change of vegetation and analyze its related affecting environmental factors in the headwaters of the Yellow River. The spatiotemporal change of vegetation coverage in the study area during the period of 2000- 2010 was analyzed using the piecewise linear regression with trend analysis and based on the Vegetation Continuous Field-MOD44 B. Furthermore,the effects of climatic and geographical factors including precipitation,air temperature,elevation and slope were also selected to develop the models for predicting the vegetation variation in the future. The results are as follows： 1 There was a high latitude zonality of vegetation coverage,and the vegetation coverage was decreased with the increase of latitude; 2 The vegetation regeneration occurred mainly in the regions south of the Zhaling Lake and Eling Lake,and its degeneration occurred mainly in the areas north of these two lakes; 3 Both temperature and precipitation were in an increase trend during the study period with increase rates of 0. 09 ℃ ·a^-1 and 8. 9 mm·a^-1 respectively. Variation of vegetation was more sensitive to temperature than to precipitation. Compared with vegetation regeneration areas,the average slope and elevation in the vegetation degeneration areas were lower,which indicated that human activities may affect the vegetation degeneration.