中文摘要：

植被在调节陆地碳平衡、气候系统中发挥了重要作用,并在生态系统服务功能提供方面占据主导地位,因此监测植被生长变化意义重大.基于AVHRR GIMMS NDVI和MODIS NDVI数据集在区域、像元两个空间尺度,研究了中国典型干旱区新疆1982-2012年间植被生长的动态变化,探讨了气候变化和人类活动对植被生长的影响.结果表明：区域尺度,1982-2012年生长季植被NDVI呈极显著增加趋势（4.09×10^-4·a^-1）;NDVI变化趋势存在明显阶段性,1998年前后分别呈极显著增加（10×10^-4·a^-1）和显著减少（-3×10^-4·a^-1）;生长季NDVI变化趋势的逆转主要发生在夏季,其次是秋季,而春季不存在逆转.像元尺度上农业区NDVI增加趋势显著;NDVI变化呈两极分化现象,剧烈变化区域多随时段长度延长而增加,尤其是显著减少区域范围快速扩张,导致区域尺度NDVI增加的停滞或放缓.研究区域植被生长受水热条件、人类活动共同控制.春、秋季的气温发挥主导作用,而夏季主要受到降水量的影响.大量施肥、灌溉面积增加等生产活动提高了农田植被覆盖,种植结构、灌溉方式等的改变降低了春季农田NDVI值,载畜量的增加则降低了部分草地的NDVI.

英文摘要：

Vegetation plays an important role in regulating the terrestrial carbon balance and the climate system,and also overwhelmingly dominates the provisioning of ecosystem services.Therefore,it has significance to monitor the growth of vegetation.Based on AVHRR GIMMS NDVI and MODIS NDVI datasets,we analyzed the spatiotemporal patterns of change in NDVI and their linkage with climate change and human activity from 1982 to 2012 in the typical arid region,Xinjiang of northwestern China,at pixel and regional scales.At regional scale,although a statistically significant positive trend of growing season NDVI with a rate of 4.09×10^-4·a^-1 was found during 1982-2012,there were two distinct periods with opposite trends in growing season NDVI before and after 1998,respectively.NDVI in growing season first significantly increased with a rate of 10×10^-4·a^-1 from1982 to 1998,and then decreased with a rate of-3×10^-4·a^-1 from 1998 to 2012.The change in trend of NDVI from increase to decrease mainly occurred in summer,followed by autumn,and the reversal wasn＇ t observed in spring.At pixel scale,the NDVI in farmland significantly increased;the NDVI changes in the growing season and all seasons showed polarization：Areas with significant change mostly increased in size as the NDVI record grown in length.The rate of increase in size of areas with significantly decreasing NDVI was larger than that with significantly increasing NDVI,which led to the NDVI increase obviously slowing down or stopping at regional scale.The vegetation growth in the study area was regulated by both climate change and human activity.Temperature was the most important driving factor in spring and autumn,whereas precipitation in summer.Extensive use of fertilizers and increased farmland irrigated area promoted the vegetation growth.However,the rapid increase in the proportion of cotton cultivation and use of drip irrigation might reduce spring NDVI in the part of farmlands,and the increase in stocking levels of livestock might lead to a decrease in N