利用2000—2017年MODIS NPP数据与气象观测数据,采用趋势分析及相关分析法,揭示了新疆地区植被净初级生产力（NPP）时空演变格局及其对气候变化响应的海拔分异性。结果表明：（1） 18 a间,新疆植被NPP年均值为145.96 g C·m^-2,以4.422 g C·m^-2·(10a)^-1速率呈不显著增长;受地形及区域水热条件的制约,植被NPP表现出北疆优于南疆、山区优于平原的分布规律。（2） NPP均值大体上随海拔的增加先增后减。在海拔<1400 m区域内,植被NPP以增势为主,向好趋势集中在天山北坡、准噶尔盆地南缘及南疆西北缘等地;在1400~3800 m海拔区域内,植被NPP主要呈弱的负增长,其中天山山区及其南麓、阿尔泰山局部等高海拔山区NPP退化严重。（3） 降水量是新疆植被生产力水平变化的主要驱动因素,但气温在高海拔（>3900 m）地区取代降水成为限制植被活动的主导因子。在不同海拔梯度下,植被NPP与气温主要呈负相关性,与降水量呈正相关性,且相关性在海拔<1400 m时有更突出的梯度差异。

Situating in an arid area with a fragile eco-environment, Xinjiang is among the regions mostly sensitive to climate change in China. The vertical zonality of vegetation and the stereoscopic change in climate in Xinjiang are obvious because of the large differences in topography. Although studying the vegetation dynamics and the changes in their climatic drivers on different elevation gradients in Xinjiang can positively help us understand the spatial differentiation of arid and semiarid ecosystems in China, previous studies still paid less attention to this. Therefore, on the basis of the MODIS NPP (net primary production) product and meteorological data from 2000 to 2017, the spatiotemporal and vertical distribution differences in vegetation NPP in Xinjiang were revealed using trend and correlation analyses. More importantly, the altitudinal gradient differences in the correlation between vegetation productivity and climate change were explored for the first time in this paper. The results showed the following: (1) in 2000—2017, there was an insignificant growth in vegetation NPP in the study area, with an average annual NPP of 145.96 g C·m^-2, and the growth rate was 4.422 g C·m^-2·(10a)^-1. Constrained by regional differences in topography and hydrothermal conditions, vegetation productivity was greater in the north than in the south and was larger in the mountain area than in the plain area. Vegetation cover varied significantly across altitudes: the main distribution area of vegetation was in the range of 300-1200 m above sea level, and the accumulated area of vegetation was 26.40×10⁶ hm². Vegetation productivity and vegetation cover were inconsistent with their vertical distribution characteristics; vegetation productivity was highest at altitudes between 1600 m and 1700 m. (2) Vegetation NPP was dominated by increasing trend in the areas of elevation <1400 m, and the increasing trend was mainly concentrated in the northern slope of the Tianshan Mountains, the southern margin of Junggar Basin, and the northwestern margin of southern Xinjiang. Vegetation NPP had a slightly decreasing trend at an altitude of 1400 to 3800 m, and the decline in productivity was more prominent at some high-altitude areas such as the Tianshan and Altai Mountains. (3) Rainfall was the major factor that affected the primary production of vegetation in Xinjiang. NPP was positively correlated with precipitation in 66.9% of the vegetated areas (6.6% was significantly correlated), which demonstrated that increased precipitation is effective in promoting vegetation productivity. At different elevation gradients, vegetation NPP was mainly negatively correlated with temperature and positively correlated with precipitation, and both correlations had more prominent gradient differences at altitudes <1400 m. This suggested that vegetation growth was more sensitive to changes in hydrothermal conditions at middle and low altitudes below 1400 m. However, in high-altitude (>3900 m) areas, temperature replaced precipitation as the dominant factor restricting vegetation activities. Under the general trend of global warming, the study of vertical patterns of vegetation systems and their climate-driven mechanisms in ecologically fragile areas like Xinjiang is of great significance for improving environmental management and ecological construction capacity.