Spatial-temporal pattern of vegetation growth and its driving factors in the Yellow River Basin of Shaanxi Province, Northwest China during 2001-2020.

Shaanxi Province is an important region for implementing the strategy of ecological conservation and high-quality development of the Yellow River Basin. Based on remote sensing data of vegetation growth, combined with meteorological raster data and digital elevation model data, we used trend analysis, partial correlation analysis, coefficient of variation, residual analysis, and relative impact analysis methods to examine the spatial-temporal varia-tion and driving factors of vegetation growth in the Yellow River Basin of Shaanxi Province during 2001-2020. The results showed that both the normalized difference vegetation index (NDVI) and gross primary productivity (GPP) exhibited a significant upward trend, with a growth rate of 0.066·(10 a)^-1 and 133.610 g C·m^-2·(10 a)^-1, respectively. Spatially, 78.0% and 92.1% of the areas showed significant increases in NDVI and GPP, respectively, with stable vegetation growth in most areas. NDVI and GPP initially decreased and then increased with increasing elevation, and peaking at slopes greater than 20°. Vegetation growth on the shady slope was slightly better than on the sunny slope. Both showed the highest growth rates at elevations of 750-1250 m and slopes of 2°-10°. The NDVI growth rate was greater on the west, southwest, and east slopes, while the GPP change trends were similar across different slope aspects. The areas where NDVI was positively correlated and negatively correlated with ave-rage temperature were approximately equal in size. About 17.0% of the area was significantly positively correlated with precipitation, and 5.6% was significantly negatively correlated with sunshine hours. The spatial distribution of GPP showed significantly positive correlation areas of 6.1% with average temperature and 12.3% with precipitation, with scattered significant correlation areas for sunshine hours. 86.3% of the area showed an improvement in vegetation growth driven by both climate change and human activities. In regions with enhancing vegetation condition, human activities had a relatively positive impact on vegetation growth, accounting for 84.5%, especially in the core areas of the project of returning farmland to forest and grassland. In regions with degradation of vegetation, areas where the relative impact of human activity exceeded 80% accounted for nearly 30%, primarily concentrated in the urban agglomeration of Guanzhong Plain.