# The Response of Vegetation Dynamics to Climate in Xinjiang from 1991 to 2018
## 1 Introduction
Studies had indicated that northwest China is experiencing warming and humidification under climate change [29; 30], and Xinjiang, the largest arid area in this region, is also facing climate transition [31; 32]. This trend has led to significant vegetation changes in Xinjiang, drawing increasing attention from scholars [33; 34; 35; 36; 37]. Currently, research on vegetation change in Xinjiang primarily focuses on analyzing the spatiotemporal variations of a single vegetation index (NDVI or LAI) and its relationships with climate factors, including air temperature, precipitation, soil moisture, and evapotranspiration. [PERSON] et al. [38] used partial correlation analysis to examine the relationship between the NDVI of grasslands and climate factors, indicating that precipitation during the growing season and summer had the most significant impact on grassland changes. [PERSON] et al. [39] compared NDVI datasets of typical arid lands, Xinjiang and Arizona, which have similar landscapes, to study the response of arid ecosystems to climatic factors. The results showed that Xinjiang had a higher NDVI anomaly growth rate, and similar types of natural vegetation exhibited responses to climate change that were controlled by temperature and humidity. [PERSON] et al. [40] analyzed the impact of climate change on Xinjiang's vegetation using NPP data, suggesting that NPP increased for most vegetation types, with precipitation and soil moisture being the most influential climate factors. Although these studies all indicate that vegetation cover in Xinjiang is increasing, discrepancies exist in the relationships derived between vegetation and climate factors. For example, [PERSON] et al. [41] argued that NDVI variation was unrelated to temperature, suggesting that precipitation may be the key factor for vegetation growth in the arid regions of northwest China. In contrast, [PERSON] et al. [32] obtained results from analyzing NDVI data in Xinjiang that were inconsistent with [PERSON] et al. 's findings. Furthermore, most studies primarily focus on the spatiotemporal changes of a single vegetation index. Differences between various vegetation indices and their relationships with climate factors can lead to uncertainty in vegetation driving mechanisms. Therefore, this study used NDVI, LAI, and GPP as vegetation indices to analyze the characteristics of vegetation changes in Xinjiang from 1991 to 2018, and to compare the differences in spatial distribution among these indices. Additionally, the response of vegetation in Xinjiang to climate change was explored by integrating the spatiotemporal variations of temperature and precipitation during the study period. The correlation distributions between different vegetation growth indices and climate factors were also compared. The spatiotemporal distributions of different vegetation growth indices in Xinjiang and their correlations with temperature and precipitation were also compared to understand the spatiotemporal differences in vegetation change (Figure 1), thus providing a more realistic reflection of vegetation dynamics and potential driving mechanisms under warming and humidification, offering support for land use management, optimizing land use planning, and reducing ecological impacts.