Oases, as complex geographical landscapes, are strongly influenced by both natural variation and human activities. However, they have degenerated because of unplanned land use and water resource development. The research of oasis changes has mostly discussed single components, but multiple components, especially spatial changes to oasis vegetation, need further strengthening. Land use and NDVI were extracted based on Landsat 5/8 and Mod13A3, respectively, and a transfer matrix was constructed to analyze changes of land use in the Hexi Corridor during 2000–2020. The significant changes in the area of each land use were also quantified. Combined with regional temperature and precipitation, interpolated from meteorological data, the correlations between regional temperature, precipitation, and vegetation coverage were calculated, especially in the quantized areas with significant associations. The results showed that the area of bare land or desert decreased, while the areas of agricultural and residential land increased. The normalized difference NDVI of the studied oases increased at the rate of 0.021 per decade, which was positively related to precipitation (p < 0.05), rather than temperature; of which, farmland and planted grass land were 55.65% and 33.79% in the significantly increased area. In the area of significant positive relation between NDVI and precipitation, the ratio of grassland, farmland, and forest was 79.21%, 12.82%, and 4.06%, respectively. Additionally, changes in oasis vegetation were determined primarily by agricultural activities, which reflected a combination of natural and anthropic influences.

Precipitation and snow/ice melt water are the primary water sources in inland river basins in arid areas, and these are sensitive to global climate change. A dataset of snow cover in the upstream region of the Shule River catchment was established using MOD10A2 data from 2000 to 2019, and the spatiotemporal variations in the snow cover and its meteorological, runoff, and topographic impacts were analyzed. The results show that the spatial distribution of the snow cover is highly uneven owing to altitude differences. The snow cover in spring and autumn is mainly concentrated along the edges of the region, whereas that in winter and summer is mainly distributed in the south. Notable differences in snow accumulation and melting are observed at different altitudes, and the annual variation in the snow cover extent shows bimodal characteristics. The correlation between the snow cover extent and runoff is most significant in April. The snow cover effectively replenishes the runoff at higher altitudes (3300–4900 m), but this contribution weakens with increasing altitude (>4900 m). The regions with a high snow cover frequency are mostly concentrated at high altitudes. Regions with slopes of 45°. The snow cover frequency and slope aspect show symmetrical changes.

Introduction: In the context of global warming, terrestrial ecosystem carbon sequestration is critical for mitigating climate change. However, quantitative estimation of vegetation carbon sinks in arid/semi-arid regions remains a key challenge for understanding global carbon cycling. This study aims to (1) quantify the spatio-temporal dynamics of vegetation carbon sinks in Northwest China (2000–2023) and (2) reveal their responses to climate drivers.Methods: In this study, by using a multi-source remote sensing dataset of long time series, vegetation Net ecosystem productivity (NEP) in northwestern China (NWC) from 2000 to 2023 was estimated. Based on the NEPs, the spatio-temporal characteristics of vegetation carbon sinks were quantitatively investigated, revealing the spatio-temporal differences in NEP among different underlying surface types. Furthermore, the response relationship between vegetation NEP and climate change was deeply explored by using partial correlation analysis.Results: (1) From 2000 to 2023, the Northwest China has served as a carbon sink, with an average carbon sequestration of 217.26 g C·m⁻²·a⁻¹ and a stable upward trend. Spatially, the regions of carbon sink exhibited a distinct zonal pattern along the China’s dry and wet climate boundary. (2) Over the 24-year period, the dynamic changes in NEP have mainly been characterized by low to moderate fluctuations, NEP in most areas of Northwest China showed an increasing trend, and future NEP is predicted to continue increasing. indicating more stable for NEP. The carbon sequestration capacity differs significantly across different land cover types, but it is increasing about total amount, especially in most areas of the Northwest, and this trend is expected to continue in the future. (3) Climate analysis shows that the temperature and precipitation are generally positively correlated with vegetation carbon sinks, while solar radiation is a negatively correlated with carbon sinks in most areas.Discussion: The research findings provide important references for vegetation restoration and protection, as well as achieving the goals of “carbon peaking” and “carbon neutrality”. Moreover, it offers scientific insights for studying vegetation carbon sinks in terrestrial ecosystems in mid to high latitude regions globally.

Investigation of extreme precipitation events in arid and semiarid regions, especially for occurrence time and the associated circulation mechanisms, is vital to support the forecasting of and the advanced response to resultant disasters. In this study, the spatiotemporal pattern of occurrence time of extreme precipitation and atmospheric circulation mechanisms in the Arid Region of Northwest China (ARNC) were analyzed using two indicators (precipitation concentration degree and period) and the climate diagnosis method. Results showed that the significant scattered pattern of extreme precipitation occurrence time (EPOT) in Northern Xinjiang and the postponed pattern of maximum extreme precipitation occurrence (MEPO) from southern to northern Xinjiang are consistent with the input pathway of the Arctic air mass. During the anomaly dispersion year of EPOT and the anomaly delay year of MEPO, the Arctic air mass carried sufficient water vapor is transported to ARNC for triggering extreme precipitation events. Meanwhile, the pattern of concentration–dispersion–concentration in eastern ARNC demonstrates interaction between the westerlies and the summer monsoon. Sufficient water vapor is transported to southwestern ARNC by the southwest monsoon during the anomaly delay year of MEPO and the anomaly concentration year of EPOT. The findings of this study suggest that invasion of the Arctic air mass and the summer monsoon could influence extreme precipitation in ARNC.