The Aksu River Basin, the main headwater of the Tarim River, contributes more than 70% of the main stream's runoff and is therefore critical in maintaining hydrological stability in this arid river system. In recent decades, rapid oasis expansion and growing agricultural water withdrawals have intensified competition for surface and groundwater, posing increasing ecological risks to the downstream Tarim River Basin. To quantitatively characterize river-groundwater hydrological responses under intensive water use, we combined statistical analysis, field observations, and distributed hydrological modeling within a basin-scale conceptual framework. Multiple lines of evidence-water level monitoring, hydrochemical tracers, stable isotopes, and the integrated surface-groundwater model MIKE SHE-were used to identify river-groundwater interaction mechanisms in the Aksu alluvial plain. Results reveal a typical three-stage spatial exchange pattern: river recharge to groundwater in the upstream reach, groundwater discharge to the river in the midstream, and renewed river infiltration to groundwater downstream. The patterns inferred from water levels, hydrochemistry, and isotopes are broadly consistent, while water-level data better resolve left-right bank asymmetry. The MIKE SHE model supports the seasonal bidirectional exchange dynamics and reproduces runoff behavior with acceptable performance (RMSE and residual standard deviation within 20% of observed means and R-2 > 0.7 during both calibration (2010-2017) and validation (2018-2021)). The proposed multi-evidence framework captures the spatio-temporal variability of river-groundwater interactions in arid regions and provides spatially differentiated guidance for conjunctive surface-groundwater regulation and integrated water resources management in the Tarim River Basin.

Land subsidence induced by excessive groundwater abstraction has emerged as a major geo-environmental hazard in arid oasis regions, calling for reproducible methods to quantitatively assess the abstraction-reduction-subsidence response and to support zoned management. This study integrates Sentinel-1A PS-InSAR deformation data with groundwater-level measurements to develop and calibrate a MODFLOW-SUB model that couples three-dimensional groundwater flow and one-dimensional skeletal compaction. The InSAR deformation field is used to constrain the conceptual model and key parameters. Four abstraction-reduction scenarios (20%, 40%, 60%, and 80%) are designed to characterize response curves using indicators such as maximum cumulative subsidence, annual subsidence rate, and the area exceeding specified thresholds. In addition, a multi-criteria composite index integrating driving forces, geological susceptibility, and exposure is applied for hazard zoning and scenario comparison. The results show that PS-InSAR constraints improve the spatial agreement of the simulations. The time-series RMSE between simulated and InSAR-derived deformation is approximately 20 mm, and the end-of-period cumulative subsidence error is within 10 mm. From 2019 to 2020, the maximum cumulative subsidence reached 166 mm, and the peak subsidence rate reached 101 mm/a. A clear lag between groundwater-level fluctuations and subsidence is observed, with the maximum correlation occurring at similar to 35 days for ACJ-1 and similar to 59-83 days for ACJ-2. This spatial variability is associated with the thickness and permeability of clay layers. Forecasts for 2021-2028 indicate that, under business-as-usual abstraction, maximum subsidence may reach 695 mm. Across scenarios, subsidence mitigation exhibits diminishing marginal returns with increasing abstraction reduction. Under the adopted model settings, a 20% reduction in abstraction yields substantial decreases in maximum subsidence and high-hazard area, representing a practical trade-off between mitigation benefits and water-use costs. Overall, the integrated workflow of monitoring, inversion, coupled modeling, scenario analysis, and zoning, together with the resulting zoned management recommendations, provides decision support for land-subsidence mitigation and water-allocation planning in arid oasis regions.

Water scarcity directly constrains the development of arid inland river basins. Quantifying surface water-groundwater (SW-GW) transformation is critical for refined water resource management. To this end, we selected the Cherchen River Basin as a representative study area. By integrating hydrochemical analysis, isotope tracing, and end-member mixing analysis, we systematically quantified SW-GW interactions under varying spatiotemporal conditions. The results show that: (1) Hydrochemical facies exhibit distinct spatial zonation, transitioning from HCO3 dominated types upstream to Cl-Na types downstream; (2) Hydrogeochemical processes are controlled by the weathering and dissolution of silicate and evaporite minerals; (3) SW mainly recharges GW in the upstream and downstream reaches, while GW discharges into SW in the midstream, with notable seasonal reversals at certain sections. These findings advance the understanding of hydrogeochemical evolution and SW-GW dynamics in arid inland basins and provide a scientific basis for sustainable water management in similar regions.

Climate change in High Mountain Asia(HMA)is characterized by elevation dependence,which results in vertical zoning of vegetation distribution.However,few studies have been conducted on the distribution patterns of vegetation,the response of vegetation to climate change,and the key climatic control factors of vegetation along the elevation gradient in this region.In this study,based on the Normalized Difference Vegetation index(NDVI),we investigated the evolution pattern of vegetation in HMA during 2001-2020 using linear trend and Bayesian Estimator of Abrupt change,Seasonality,and Trend(BEAST)methods.Pearson correlation analysis and partial correlation analysis were used to explore the response relationship between vegetation and climatic factors along the elevation gradient.Path analysis was employed to quantitatively reveal the dominant climatic factors affecting vegetation distribution along the elevation gradient.The results showed that NDVI in HMA increased at a rate of 0.011/10a from 2001 to 2020,and the rate of increase abruptly slowed down after 2017.NDVI showed a fluctuating increase at elevation zones 1-2(<2500 m)and then decreased at elevation zones 3-9(2500-6000 m)with the increase of elevation.NDVI was most sensitive to precipitation and temperature at a 1-month lag.With the increase of elevation,the positive response relationship of NDVI with precipitation gradually weakened,while that of NDVI with temperature was the opposite.The total effect coefficient of precipitation(0.95)on vegetation was larger than that of temperature(0.87),indicating that precipitation is the dominant control factor affecting vegetation growth.Spacially,vegetation growth is jointly influenced by precipitation and temperature,but the influence of precipitation on vegetation growth is dominant at each elevation zone.The results of this study contribute to understanding how the elevation gradient effect influences the response of vegetation to climate change in alpine ecosystems.

The escalating conflict between agricultural and ecological water demands, intensified by global climate change, poses significant challenges for water resource allocation in arid inland river basins. This study investigates the potential for integrated management of multiple water sources within the context of the Tarim River, Cherchen River, and Taitema Lake area. For the first time, we developed a joint distribution model of runoff for the Tarim and Cherchen Rivers, informed by the dynamics of Taitema Lake, to assess collaborative allocation strategies for terminal lake management in arid environments. Utilizing measured runoff data from 1960 to 2021, we employed a Bayesian vector autoregression model (BVAR) to analyze hydraulic connections between the rivers and the lake. Multivariate empirical mode decomposition (MEMD) was applied to identify periodic characteristics of runoff, while wavelet coherence transform assessed the consistency of runoff patterns. A Copula function was then utilized to construct a joint distribution model, quantifying variability patterns and their cascading effects on ecological water use in Taitema Lake. Findings reveal that the Cherchen River contributes more significantly to Taitema Lake than the Tarim River, exhibiting stable flows compared to the latter’s fluctuations. Significant lead-lag differences in flows were identified, with primary cycles of 2.9 years for the Tarim River and 5.7 years for the Cherchen River. The Copula model demonstrated a 44.52 % probability of synchronous wet-dry year occurrences, compared to 55.48 % for asynchronous occurrences. The complementarity between the Tarim River and the Cherchen River during wet and dry runoff encounter scenarios provides a foundation for establishing an efficient joint scheduling system and enhancing regional water use efficiency. This study underscores the critical role of strengthening multi-source water coordination and deepening understanding the dynamics of wet-dry runoff transitions to enhance water security and optimize resource management in arid regions.

To explore the spatial distribution and formation mechanism of underground salty water in the Aksu River Basin， 443 sets of effective groundwater samples were collected and analyzed by comprehensively applying mathematical statistics， hydrochemical analysis， and inverse hydrological earth simulation methods. The results showed： ① The brackish water distribution area covered 0.55×104 km2 in the Aksu River Basin， which represented 44.33% of the total plain area. This brackish water was mainly distributed in the lower reaches of the Aksu River Basin. Overall， its distribution demonstrated an east-west diffusion pattern influenced by local factors such as river flow， geological units， and groundwater flow directions. ② The composition of ions in the brackish groundwater primarily originated from the dissolution of evaporated salt rocks， followed by the weathering of silicate rocks and limited dissolution of carbonate rocks. As each salt rock dissolved to a certain threshold， sulphate or carbonate precipitates were released， leading to reduced concentrations of Ca2+， Mg2+， SO42-， and HCO3- ions and a transformation of water chemistry to Cl--Na+ type. ③ The factors influencing the formation of salty underground water， in descending order of impact， included evaporation and concentration， water-rock interactions， and cation exchange. Evaporation and concentration notably contributed to elevated concentrations of brackish groundwater. The dissolution of evaporated saline rocks significantly influenced the formation of brackish groundwater， with cation exchange exerting a stronger influence compared to that of carbonate rocks. ④ In the upper reaches of the watershed， the transfer of substances followed the sequence： evaporated saline rocks &gt; carbonate rocks &gt; cation exchange （reverse）. Conversely， in the lower reaches， the sequence shifted to evaporated saline rocks &gt; cation exchange （forward） &gt; carbonate rocks. These findings are pivotal for the sustainable management and utilization of brackish water resources in the Aksu River Basin， aiming to foster the region's water resource sustainability.

The geological environment of the arid region in northwest China is unique， characterized by a long-term scarcity of water resources， which results in an extremely fragile ecosystem. In this context， studying the changes in carbon storage characteristics and the driving factors of spatial differentiation before and after the implementation of ecological restoration projects can provide a scientific basis for ecological restoration and sustainable development in arid regions. Based on land use data from 2008， 2013， 2018， and 2023， the study analyzed and predicted land use changes and carbon storage under different historical and future scenarios and explored the driving mechanisms. The study produced several interesting results： ① The spatial distribution pattern of land use changed significantly during 2008-2023. The expansion of cultivated land area was the most significant change， an increase of 12.89×104 hm2. ② During 2008-2023， the total carbon storage showed an increasing trend， increasing by 483.97×104 t. ③ Temperature is the main driving factor affecting the spatial distribution of carbon stocks （q value of 0.513）， and the interaction between annual average temperature and distance to government detected by the interaction factor is the main driving factor affecting the spatial distribution of carbon stocks （q value of 0.605）. ④Carbon storage is predicted to show an increasing trend in 2028 under the three scenarios of natural development， ecological protection， and dual protection of farmland ecology. Carbon storage will increase significantly in the ecological protection scenario， but the dual protection of ecology and farmland scenario increases farmland area while protecting the ecology and improving carbon storage. This study provides technical support for evaluating the ecological restoration effectiveness of the Shanshui Project and also provides a scientific reference for local realization of the carbon peaking and carbon neutrality goals. ⑤ With the implementation of ecological restoration projects， the area of ecological land in the region has increased in comparison to the period prior to these projects. Moreover， carbon storage has transitioned from a reduction of 382.95×104 t in the previous period to an increase of 277.2×104 t， indicating the significant effectiveness of the ecological protection initiatives.

Arid inland oases depend on groundwater, yet many basins face co-occurring water scarcity, salinization risk, and ecological vulnerability. We examined the Cherchen River Basin to clarify how aquifer structure, water-table position, and water quality jointly constrain sustainable oasis use. We asked three questions: what are the basin-scale patterns of aquifer architecture and groundwater depth, how do groundwater, irrigation water, and surface water qualities vary spatially, and where salinization is risk most acute. We hypothesized that shallow phreatic levels coincide with salinization hotspots and that proximity to human activities is associated with degraded groundwater quality. Using integrated field surveys, pumping tests, hydrochemistry, geophysics, and GIS mapping, we produced basin-wide layers of groundwater depth and quality and evaluated irrigation suitability against national standards. The aquifer is a thick, single porous system with marked south–north gradients; shallow water tables dominate irrigated zones, indicating high evaporative risk. Groundwater quality is spatially heterogeneous, with localized degradation near human activity; most irrigation sources are usable, although outliers with high salinity and chloride pose soil risks. Surface water quality is generally acceptable but nutrient enrichment warrants attention. The results provide a decision basis for targeted drainage, irrigation efficiency upgrades, and groundwater protection to mitigate salinization and support long-term ecological security in arid inland basins.

Identifying the temporal and spatial variations of vegetation cover and their driving factors in the mainstream of the Tarim River is crucial for protecting the ecosystem stability in the basin. Based on the normalized difference vegetation index （NDVI）， climate， topography， and anthropogenic factors of the mainstream of the Tarim River from 2000 to 2020， the spatiotemporal dynamic variation characteristics of NDVI in the mainstream of the river during 2000 and 2020 were analyzed by Theil-Sen Median slope estimation， Mann-Kendall trend significance test， Hurst index， and geographic detector， and the influencing factors of NDVI were evaluated. The results of the study follow： ① During 2000 to 2020， the NDVI in the mainstream of the Tarim River showed a fluctuating upward trend， with an increase rate of 0.001 2 per year， mainly dominated by low vegetation cover， accounting for 59.4% of the area. The spatial distribution of NDVI was obvious， with 44.9% of the area showing an increasing trend. ② The Hurst index analysis indicated that 64% of the NDVI area showed an improvement trend， while 36% of the area showed a degradation trend. ③ The influence detection showed that elevation was the main driving factor， with a q value of 0.421 9， and that the interaction between air temperature and elevation was the most significant effect， with a q value of 0.532. The ecological detection showed that there was a continuous significant difference between precipitation and air temperature on the change of NDVI， while there was no significant difference between slope aspect and night light. ④ The spatial differentiation of NDVI in the upper reaches of the river is primarily caused by the combined effects of climatic factors and topographic factors， but in the middle reaches， there is a gradual transition to human factors. Human factors are the dominant factors in the downstream region. Therefore， the NDVI in the mainstream of the Tarim River has shown an improvement trend through the past 20 years， and the NDVI situation in the region will depend more substantially on the balance of hydrothermal conditions in the future.

Groundwater pollution of the loess plateau regions has become a global concern due to its vulnerability to natural and anthropogenic influences. In this study, 146 water samples were investigated to identify the spatiotemporal variability in groundwater chemistry, pollution sources and nitrate health risks in two interconnected river basins of a typical loess region. The results showed that except for bicarbonate, spatiotemporal variability of hydrochemical components in Malian River Basin (ML) was generally greater than that in Upper Jinghe River basin (JH-U) due to the hydrogeological conditions, and the hydrochemical facies in two river basins transformed from SO4·Cl and Cl·SO4 types to HCO3 and HCO3·SO4 types. The results of integrated-weight quality index (IWQI) showed that 77.8 % (1970s), 33.3 % (2004), 34.3 % (2015) of samples in ML exceeded the standard limits of Class IV groundwater quality, displaying a high pollution level with an improvement trend, while groundwater quality in JH-U indicated a very low pollution level with a deterioration trend. The geogenic source was identified as a main factor affecting groundwater quality, with contributions of 59.2 % and 48.7 % in JH-U and ML (2015), respectively. The anthropogenic sources including agricultural activities (20.7 % and 21.8 % in JH-U and ML) and coal mining activities (20.1 % and 29.5 % in JH-U and ML) also played a role in affecting groundwater quality. The nitrate health risk assessment demonstrated that 39.1 % and 20.3 % of groundwater samples (2015) significantly exceeded the standard threshold (Hazard Index = 1), implying a higher health risk to children than adults, and the nitrate health risk in ML was obviously greater than that in JH-U. This study provides novel insight into the spatiotemporal variability in groundwater chemistry, quality and health risk in loess regions under the influence of geogenic and anthropogenic factors.

Groundwater management is a relatively weak aspect of water resources management in the Huai River Basin. It is necessary to understand the characteristics and patterns of groundwater changes. Based on GRACE and GLDAS data from 2003 to 2023, the groundwater storage anomalies (GWSA) were calculated in the Huai River Basin. Combined with the Normalized Difference Vegetation Index (NDVI), water resources bulletin, and other datasets, this study used STL time series decomposition and random forest to focus on the spatiotemporal changes and the possible causes of groundwater storage. The results indicated that GWSA in 80.71

Understanding snow cover dynamics and their driving factors in High Mountain Asia (HMA) is crucial for regional hydrology and water resource management. While previous studies have explored spatial and temporal variations in snow cover and phenology, quantitative relationships between snow cover dynamics and their drivers under spatial heterogeneity remain unclear. This study is based on MODIS snow remote sensing images, extracting the snow cover percentage (SCP) and snow cover frequency (SCF) indices. Spatial heterogeneity was validated and classified into cold spots (areas with low SCF values), hot spots (areas with high SCF values), and random areas (areas with non-significant SCF values) using Moran's I index and the Getis-Ord Gi* method. Snow cover change trends were analyzed, and the GeoDetector model quantified the influence of driving factors. Results revealed a decreasing trend in SCP (-0.03 %/year) and SCF (-0.024 %/year) from 2001 to 2023, with distinct spatial variations. Cold spots exhibited the lowest SCF (5.63 %-8.51 %) and continuous decline, driven primarily by elevation and temperature (T). Hot spots showed the highest SCF (63.37 %-69.26 %) and continuous increase, influenced by wind (W), snowfall (SF), and precipitation (P). Random areas, characterized by seasonal snow cover (SCF: 26.16 %-34.51 %), exhibited minor variations, driven by a combination of factors. This study highlights the significant role of spatial heterogeneity in shaping snow cover dynamics across HMA and provides new insights into cryospheric hydrology. These findings contribute to improved understanding of hydrological cycles and inform water resource management strategies under changing environmental conditions.

Arid inland river basins exhibit pronounced uncertainty and spatial heterogeneity in carbon storage dynamics due to extreme climate conditions, water scarcity and ecosystem vulnerability. In particular, water-depleted zones still lack systematic research on the evolution mechanism of carbon storage. To assess the evolution characteristics of carbon storage in such regions, this study developed an integrated framework combining the Patch-generating Land Use Simulation (PLUS) model, the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model and a Structural Equation Model (SEM), taking the Tarim River mainstream as a representative case. It systematically analyzed the spatial and temporal evolution of land use/cover change (LUCC) and carbon storage from 1990 to 2020, simulated future trends under three scenarios: natural development (ND), cultivated land protection (CP) and ecological protection (EP), covering from 2030 to 2050, and quantitatively identified the direct and indirect drivers of spatial differentiation in carbon storage. The results revealed that over the past three decades, the most significant land transitions in the Tarim River mainstream occurred in cultivated and build-up land. Among the three scenarios, within the EP scenario, the reduction in carbon storage by 2030, 2040, and 2050 was significantly alleviated, with an additional 56 x 105 tons of carbon stored compared to the cultivated land protection scenario. LUCC emerged as the dominant directly driver of regional carbon storage changes. Additionally, carbon storage in the upper, middle, and lower reaches was indirectly influenced by socio-economic and natural geographical factors, with the dominant factor varying by region. These differences modified water resource supply patterns, influenced vegetation dynamics, and ultimately indirectly affected the spatial and temporal evolution of carbon storage. This study enriches the understanding of carbon storage evolution mechanisms in arid regions and underscores the importance of regionspecific carbon management strategies tailored to local conditions.

Groundwater serves crucial roles in resource preservation, ecological maintenance, and geological security in addition to being a significant component of water supplies. This work meticulously summarized data on the growth and consumption of water resources, hydrogeological survey, and groundwater inquiry and evaluation since 1959 to 2021 to estimate the evolution of the recharge, discharge, and storage of groundwater in the Hami Basin. The results suggest that: 1) Human activities primarily influenced the evolution of the groundwater recharge and discharge factor in the Hami Basin, and the abrupt changes in recharge and discharge were consistent with the implementation of policies such as reform and opening up and western development, which is a key factor in controlling human activities; 2) Total groundwater recharge fell from 8.22 × 108 m3/a in 1959 to 4.08 × 108 m3/a in 2021. The discharge of groundwater has reduced from 8.21 × 108 in 1959 to 5.67 × 108 m3/a in 2021; and 3) The equilibrium between groundwater recharge and discharge was disrupted in 1975, and ever since then, the discharge has always been greater than the recharge, indicating a negative equilibrium state. The total amount of storage over the last 45 years was –71.3 × 108 m3.

The Kuitun River Basin, a typical arid area, is in Northwest China where water resources are extremely scarce. Comprehensive analysis of the hydrochemical characteristics and main types of groundwater in the plain area of the basin was conducted, revealing that the ion source and evolution law are helpful for evaluating water quality and water supply. In this study, 316 groups of groundwater samples were collected from 2017 to 2019. Descriptive statistics, correlation analysis, Piper three-line diagram, Gibbs diagram, principal component analysis (PCA), hierarchical cluster analysis (HCA), ion ratio method, and saturation index were used to evaluate hydrochemical characteristics, ion sources, and water quality of the groundwater. The results show that (1) the concentration of ions in groundwater varied greatly over region. Along the flow direction of groundwater, the concentration of ions in the fine soil plain diving (FSPD) increased more than that of gravel plain diving (GPD), and the areas with high ion concentrations were mainly distributed in the northeast of the study area. (2) There were 29 hydrochemical types in the study area. (3) The chemical ions originate from the evaporation, concentration, dissolution, and filtration of rocks. Both diving water and artesian water had different degrees of cation alternating adsorption, and the degree of exchange adsorption was as follows: fine soil plain artesian > FSPD > GDP. (4) Combined with the drinking water quality standards and irrigation suitability evaluation criteria in the study area, observations were as follows: drinking water quality in the study area has a regular deterioration trend from south to north, most groundwater is suitable for irrigation water, and a small portion of groundwater exhibits moderate Na+ hazard and is highly endangered by salinity.

准确查明苦咸水分布、水化学特征及成因对此类非常规水资源的开发利用及当地水安全保障能力的提高具有重要意义.通过对新疆阿拉尔市地下水进行采样分析,利用水化学图解、描述性统计分析、离子比值法、饱和指数法等方法分析苦咸水的水化学特征及形成机制.结果表明,研究区苦咸水水化学类型以HCO3·SO4·Cl-Na·Ca·Mg、SO4·Cl-Na·Mg 和 SO4·Cl-Na 型为主,苦咸水分布面积2163.45 km2,占总面积的77.26％,主要分布在平原水库下游及塔里木河在该市范围内的后段,苦咸水的形成主要受蒸发-浓缩作用的影响,其次是岩石风化作用,同时,人类活动对研究区苦咸水的空间分布也施加了一定的积极影响.

奎屯河流域是中国西北干旱内陆地区典型的地下水高氟、高砷区,由于该地水资源匮乏,地下水是奎屯河流域农业灌溉、工业及生活供水的主要水源. 识别奎屯河流域地下水水化学特征、演变规律及其形成原因对于合理开发利用与保护管理该流域地下水资源,保障流域社会经济可持续发展与生态安全具有重要意义. 为评价奎屯河流域平原区地下水质量及变化趋势,于2017—2019年采集地下水样品316组,综合运用描述性统计、空间分析、Piper三线图、Gibbs图、离子比值法、饱和指数等方法系统分析了地下水水化学组分空间分布、水化学特征、演变规律和成因. 结果表明:①地下水化学组分在空间分布上存在较大的离散型和波动性,山前砾质平原区潜水化学类型为HCO3%SO4-Na%Ca型,细土平原区潜水为SO4%Cl-Na%Ca型,承压水为HCO3-Na%Ca、HCO3%SO4%Cl-Na型. ②地下水中离子主要来源于岩石溶滤与蒸发浓缩作用,其中K+、Na+主要来源于岩盐溶解,SO4 2－、Cl－主要来源于蒸发岩溶解,Mg2+和Ca2+部分来源于蒸发岩溶解,部分来源于硅酸盐和碳酸盐溶解. CaCO3 及CaMg(CO3) 2 在细土平原区潜水中呈饱和状态,在承压水及砾质平原区潜水中未饱和,而CaSO4 在地下水中均未达饱和.③研究区地下水均发生了不同程度的阳离子交替吸附作用,作用的强弱程度表现为细土平原区承压水＞细土平原区潜水＞砾质平原区潜水. 研究显示,研究区由南向北离子浓度逐渐增大,蒸发岩溶解为离子的主要来源.