基于2001—2017年250 m空间分辨率MODIS NDVI数据,利用线性趋势、相关性分析等方法对新疆玛纳斯河流域NDVI时空变化格局和驱动因素进行了研究。结果表明:2001—2017年玛纳斯河流域整体NDVI呈显著增加趋势,夏季流域NDVI增长趋势最为显著,秋季流域NDVI增长趋势次之,春季和冬季流域NDVI未表现出显著的增长趋势;耕地NDVI仅在夏季呈现出极显著的升高趋势,草地在夏季和秋季均表现出极显著增长趋势,但年增长速率低于耕地,而林地和裸地在4个季节均未呈现增长趋势;单位面积草地、林地、裸地NDVI增加主要受降雨量驱动,单位面积耕地NDVI与气象因素未发现相关性;2001—2016年研究区耕地面积急剧增长,耕地面积与流域植被生长旺季整体NDVI变化趋势存在显著的正相关关系,而与同期气温、降水变化没有显著相关性。2001—2017年玛纳斯河流域NDVI显著增加趋势主要是由人类农业生产活动引起的耕地扩展所驱动,而气象是次要因素。

Based on the MOD13Q1 dataset from 2001 to 2017 in the Manas River Watershed,the spatial-temporal variation of NDVI and the main driving factors were analyzed by using the methods of linear regression and correlation analysis.The results showed that the annual NDVI of the Manas River Watershed significantly increased in the past 17 years,especially in the seasons of summer and autumn with increment magnitudes at 0.006 2,0.004 0 per year,respectively.However,the annual NDVI in spring and winter did not show significant increase trends.The annual NDVI of cropland showed a very significant increase in summer,and the annual NDVI of grassland showed a significant growth trend in both summer and autumn,but with a lower rate than that of cropland.Meanwhile,the annual of forest land and bare land did not show increase trend in four seasons.Spatially,there is heterogeneity in the trend of NDVI change.The NDVI in the central part of the basin showed the most significant increase.The annual of NDVI per unit area of grassland,forest land,and bare land were mainly driven by rainfall,but it has no significant relationship with temperature.However,there was no correlation between the overall annual NDVI of the Manas River Watershed and climate factors.The cropland in the study area increased rapidly during 2001—2017.The area of cropland showed a significant positive correlation with the annual NDVI in the growing season.As a result,it was evident to conclude that the vegetation change in this region was mainly affected by human activities.