中文摘要：

为全面认识陕西省植被覆盖变化的时空特征,利用MODIS归一化差值植被指数（NDVI）,采用最大值合成法和像元二分模型对陕西省2000—2014年植被覆盖度进行提取并分析其时空变化规律,从气候因子和人类活动两方面对NDVI变化的原因进行探讨。结果显示：2000—2014年陕西省NDVI值呈波动上升趋势,总体上以0.4%/a的速率增长;植被覆盖呈明显的地域分异特征,从陕北到陕南植被覆盖度呈现由低到高的趋势;陕西省NDVI与年降水量呈显著正相关关系,可决系数为0.383;年降水量的增大及退耕还林、封山育林等工程的实施是植被覆盖度增大的主要原因。

英文摘要：

In order to understand the spatial-temporal features of vegetation change in Shaanxi Province,vegetation coverage from year 2000 to 2014 in Shaanxi Province was extracted from the Nor^na1ized Difference Vegetation Index （ NDV7） which obtained from the Moderate Reso-lution Imaging Spectroradiometer （ MODIS） data and was used to analyze the spatial-temporal variation features of vegetation by using the maximum va1ue composites and dimidiate pixe1 mode1. The possib1e reasons for vegetation change were discussed from two aspects of c1imate factors and human activities. The results show that the value of NDV7 in Shaanxi Province during the period of 2000 and 2014 increased vola-tility at the rate of 0.4%/a. The spatial distribution and change of vegetation demonstrated an obvious characteristic of regional differentiation, which transferred from low vegetation cover to the high vegetation cover. There is a significant positive correlation with R-squared 0.383 be-tween NDV7 and annual precipitation. The increase of rainfall and the implementation project of returning farmland to forest and forestation in Shaanxi Province were the reasons for the increase of vegetation coverage.