## 1 Introduction
Temperature and precipitation are generally considered two key climate factors that control vegetation growth and photosynthetic activities [9; 24; 25]. The rate of photosynthesis and respiration in vegetation is affected by temperature. Vegetation growth is sensitive to precipitation variations in arid and semi-arid areas. Previous studies have shown that precipitation is the most important factor that controlled vegetation growth in the central and northernmost regions of Xinjiang from 2000 to 2010 [11]. Vegetation growth has a closer correlation with precipitation than temperature in Xinjiang [24; 26], and climate warming might prevent vegetation growth in Xinjiang [25]. The relationship between climate and ecosystem indicators could vary based on the extent of human activities and across different climate zones [27; 28]. However, the factors dominating ecosystem indicator changes in Xinjiang across different climate zones are still unknown. Both climate change and human activities impact ecosystems, which may affect the spatial differences in ecosystem patterns. Although many studies examined the correlation between ecosystem indicators and climate factors, there is a need to examine how the relationship between ecosystem indicators indicators and climate factors varies across climate zones. In addition, human activities could likely impact vegetation growth in arid and semi-arid regions. There is a need to enrich our understanding of the impact of human activities on ecosystems for sustainable development. In essence, it is meaningful to improve our understanding of the role of climate change and human activities in vegetation changes for regional developments. Quantitatively assessing the impacts of climate change and human activities on ecosystems is still a challenge that involves mathematical and statistical methods, including PCA (principal component analysis) and correlation analysis [29]. Uncertainty exists in both the processes and the driving factors of the ecosystem change. A single-scale analysis of driving factors may misestimate the actual impact of influencing factors. Residual analysis can avoid the disadvantages of single-scale analysis. This method has been used in studying different types of ecosystems [9; 12; 30; 31; 32; 33] and across different regions, such as the Loess Plateau [9], Central Asia [13], the Belt and Road Initiative Region [30] and Africa [34]. Both temperature and precipitation in Xinjiang have increased in recent years [8; 11], and the rate of increase in temperature is much higher than the global level [7]. The local ecosystem in arid and semi-arid areas is fragile and particularly sensitive to climate change [8; 35; 36; 37; 38]. In addition, over the past half-century, Xinjiang witnessed rapid population growth and expanded areas of human activities (e.g., cultivation and grazing) [26; 39; 40; 41]. Xinjiang is one core region of China's \"Belt and Road\" initiative and plays an important role in business logistics in Europe with Asia. The society and economics in Xinjiang have experienced rapid development in the past two decades. From 2000 to 2018, the population in Xinjiang increased by more than one-third. Meanwhile, the economic growth rate exceeded the average in China [42]. Studying Xinjiang would benefit our understanding of how human activities and climate variation affect local ecosystems inland arid and semi-arid regions. The objectives of this study were to (a) analyze the responses of ecosystem indicators to climate factors and human activities in Xinjiang using satellite-based products and (b) investigate the cause of changes in the ecosystem indicators using the residual analysis approach.