Search Results (23,325)

Climate change may alter both basin-outlet water availability and runoff responses within large semi-arid tributaries. We evaluated climate-driven runoff changes at four gauged catchments in the Jinghe River Basin using a 16-gauge, multi-gauge EA-LSTM. Thirty-one NEX-GDDP-CMIP6 model–grid configurations were evaluated against 1960–2014 observations from 66 stations, and four models with strong historical statistical agreement and complete scenario records formed the screened ensemble. Native NEX-GDDP-CMIP6 forcing was used directly. At the Zhangjiashan outlet, test-period NSE and KGE were 0.823 and 0.615, respectively, while PBIAS was −31.6%. Under late-century SSP585, annual runoff decreased at Jingheyuan and Zhanghe but increased at Jingcun and Zhangjiashan, ranging from −16.7% at Zhanghe to +16.8% at Jingcun; flood-season responses showed a similar upstream–downstream contrast. At Zhangjiashan, screened-ensemble means were 0.2–11.5 percentage points lower than the corresponding expanded-ensemble means across the scenario–period combinations. Within the present input set and learned relation, precipitation and runoff changes were associated (Pearson r = 0.918), although this does not establish physical attribution. Full article

Traditional villages in ecologically sensitive areas face structural dilemmas between preservation-induced stagnation and excessive commercialization under the combined pressures of rural revitalization and ecological protection. This study investigates the spatial differentiation and revitalization strategies of 250 nationally recognized traditional villages in the Xin’an River Basin from a resilience-inspired spatial planning perspective. GIS-based kernel density estimation and the Nearest Neighbor Index were applied to characterize spatial distribution patterns, while GeoDetector was used to evaluate the explanatory power of key natural and anthropogenic factors. The Minimum Cumulative Resistance (MCR) model was used to construct revitalization-suitability zones; resilience capacities were not directly measured; instead, they were used as heuristic planning concepts for interpreting the three consolidated priority regions: Core Conservation (absorptive), Moderate Revitalization (adaptive), and Ecological Conservation (transformative/reserve). The results reveal a pattern of small-scale clustering and large-scale dispersion. A total of 69.2% of the villages were located within 1.5 km of rivers, and 95.2% were situated below 500 m in elevation. Distance to rivers (q = 0.2345) and distance to roads (q = 0.1441) showed the highest explanatory power among the eight candidate factors. The framework provides resilience-inspired spatial guidance for balancing heritage conservation, ecological protection, and rural revitalization. Full article

Heavy and extra-heavy oils represent a large and growing share of recoverable hydrocarbon resources, yet their extreme viscosity, high heteroatom content, and non-Newtonian behavior routinely defeat empirical correlations developed for conventional crude. Machine learning has emerged as a candidate response to this modeling gap, but existing reviews largely catalog applications without asking whether the technology is actually ready for industrial deployment. This critical review synthesizes machine learning applications across five thematic domains of the heavy-oil value chain: physicochemical property prediction, enhanced oil recovery, flow assurance, reactive recovery, and downstream upgrading. Studies are read through a three-phase historical lens, tracing the field’s progression from empirical-correlation replacement to methodological diversification to physics-informed and closed-loop integration, and evaluated against a Technology Readiness Level (TRL) scale adapted specifically for heavy-oil machine learning. The multilayer perceptron anchors more of the primary corpus than any other architecture, a pattern that, in our interpretation, reflects small-sample, low-dimensional regression needs rather than any demonstrated advantage over other architectures. Enhanced oil recovery is the only cluster to reach organizational-scale deployment, anchored by a single multi-decade operator program, Chevron’s San Joaquin Valley i-field; the remaining clusters are constrained less by modeling sophistication than by single-basin datasets and undisclosed uncertainty. Measured against three falsifiable deployability criteria, fidelity preservation below 10° API, operator-grade interpretability, and demonstrated laboratory-to-field transferability, no study in the reviewed corpus is documented to satisfy all three simultaneously; because industrial implementations are frequently proprietary, this is a statement about the published record identified by this search, not a claim that the capability does not exist. Federated learning, physics-informed architectures, and sequence-aware models emerge as the directions most likely to close this gap. Full article

Flash floods are among the most damaging hydrometeorological hazards in the Western Balkans (WB), yet regionally consistent, cross-border susceptibility assessments remain scarce because of fragmented national datasets and differing methodological standards. This study develops a harmonized, cloud-based flash-flood susceptibility framework for the WB (208,052 km²) by implementing a physiography-based modified Flash-Flood Potential Index (FFPI) in Google Earth Engine (GEE) at 30 m resolution. The modified FFPI integrates slope, land cover, soil texture, vegetation exposure (Bare-Soil Index), and soil erodibility, and is aggregated across 9524 EU-Hydro sub-basins to produce an operational catchment-level ranking. Additionally, CHIRPS-derived maximum daily precipitation is used to derive a rainfall-triggered hotspot layer that highlights sub-basins where terrain-controlled susceptibility coincides with strong observed rainfall extremes over the 2001–2025 period. Enhanced susceptibility is concentrated in Adriatic and Aegean-facing mountain basins of Albania, Montenegro, and North Macedonia, with 44.2% of sub-basins classified as high or very-high susceptibility. Multi-source validation against inventoried torrential catchments, published GIS-based susceptibility maps, and flood records yielded moderate to very strong agreement (68.6–92.0%), together with an AUC-ROC of 0.79 and F1-score of 0.77 for the pooled orthophoto-based validation dataset (n = 336 sub-basins). The framework provides a reproducible transboundary tool for regional flood-risk screening and demonstrates the potential of cloud-based geospatial platforms to overcome cross-border data fragmentation in hazard assessment. Its main limitations are the static physiographic nature of the FFPI, the coarser resolution of CHIRPS and SoilGrids relative to small sub-basins, and possible overestimation in karst terrains where subsurface drainage reduces surface runoff. Full article

Transitioning cultivated land from a narrowly defined production resource into a coordinated multifunctional asset is a cornerstone of agricultural modernization. Despite this imperative, current land utilization in China remains largely constrained by a singular production focus, resulting in suboptimal multifunctionality. Although digitally driven agricultural new quality productive forces (ANQPFs) are posited as a critical catalyst for functional restructuring, empirical evidence quantifying their relationship with cultivated land multifunctionality (CLM) remains limited. To examine the association between ANQPF and CLM, this study employs panel data from 115 prefecture-level cities across the Yangtze River Basin, China, spanning the period 2013–2023. The empirical results indicate that ANQPF is significantly and positively associated with CLM. These associations are robust to a battery of robustness checks, and endogeneity tests provide additional evidence supportive of a positive association. Transmission pathway analysis suggests that the positive association operates through three pathways: increasing the main business revenue of agricultural product processing enterprises above a designated size, expanding the number of agricultural technology patents, and improving the level of agricultural socialized services. Subgroup analyses, supplemented by Chow tests of coefficient equality, reveal that these associations tend to be larger in non-major grain-producing regions, areas with lower per capita GDP, and the upper and middle reaches of the Yangtze River Basin. Threshold effect analysis further demonstrates that once ANQPF exceeds a certain level, the positive association exhibits diminishing marginal returns; a similar but weaker pattern is observed for leading enterprises. These findings provide policy implications for developing ANQPF in accordance with local conditions and for synergistically optimizing CLM patterns. Full article

To address the critical challenge of extracting short-period surface deformation signals induced by extreme floods from InSAR time series, this study focuses on the catastrophic flood that struck the Haihe River Basin in July 2023 (hereinafter referred to as the “23·7” flood, with a total duration of approximately 65 days) and proposes a novel method for transient deformation signal extraction. Using Sentinel-1A satellite data and the PS-InSAR technique, we constructed a multivariate composite fitting function comprising a linear trend term, annual and semi-annual seasonal terms, a step term, and a logarithmic decay term. Through nonlinear least-squares fitting, this approach achieves effective separation of long-term tectonic deformation, seasonal fluctuations, high-frequency noise, and transient flood-related signals. The results show that the W-shaped floodplain east of Xiong’an New Area does not exhibit the expected subsidence induced by water loading but instead features pronounced surface uplift of up to 30 mm. Multi-physics forward modeling reveals the underlying mechanism: the elastic subsidence caused by surface water loading, calculated via the LoadDef spherical loading theory, amounts to only ~2 mm. In contrast, forward modeling based on the GMS three-dimensional groundwater seepage model and the principle of effective stress indicates that the pore water rebound effect can produce surface uplift of up to ~36 mm. The superposition of these two effects is highly consistent with InSAR observations in terms of magnitude, direction, and spatial distribution, confirming that the flood-induced surface deformation is dominated by the pore water rebound effect driven by rapid groundwater recharge, rather than subsidence from water loading. The proposed framework extends the application potential of geodetic techniques for monitoring short-period extreme hydrological events. Full article

Integrated watershed sustainability assessments are still incipient in Ecuador, where scarce and heterogeneous data are limiting factors. This study introduces the Watershed Sustainability Index (WSI) to the Chibunga Basin in Chimborazo, Ecuador, marking its first application in this region. A key aspect of this study is the development of a clear and reproducible method for applying the index, particularly in inter-Andean basins where data are limited. The four dimensions—Hydrology, Environment, Life, and Policy—were assessed through the Pressure–State–Response (PSR) framework by combining secondary statistics, field sampling, GIS land-use analysis, and a two-round Delphi consultation with ten experts to operationalize the institutional (Policy) component. The basin scored 0.38 (low sustainability), with a critical Hydrology dimension (0.08), poor Policy dimension (0.33), moderate–low Life dimension (0.42), and moderate Environment dimension (0.67). The central finding goes beyond these scores: the operationalized PSR framework pinpointed where the management cycle breaks down in practice. Systematically null response scores reveal that unsustainability stems from the failure to translate an existing regulatory framework into formal institutional action, rather than from regulatory absence or physical water scarcity alone, further constrained by unfavorable socioeconomic conditions. The procedure turns the WSI from a scoring tool into a diagnostic one, providing a replicable reference for data-scarce Andean basins. Full article

Long-term exploitation of ion-adsorption rare earth deposits has played a vital role in ensuring the supply of strategic mineral resources. However, intensive mining activities have also resulted in severe ecological degradation, including vegetation loss, land degradation, and soil erosion. Although the Remote Sensing Ecological Index has been widely used for ecological environment assessment, it inadequately characterizes land degradation in ion-adsorption rare earth mining areas, while its fixed-weight framework is unable to effectively capture the influence of localized ecological limiting factors. To address these limitations, this study selected a typical ion-adsorption rare earth mining area in southern Jiangxi, China, as the study area. A Desertification Difference Index was incorporated into the conventional RSEI framework to establish a five-dimensional evaluation system consisting of greenness, wetness, dryness, heat, and desertification. Furthermore, a Dynamic Variable-Weight Remote Sensing Ecological Index (DV-RSEI) was developed by integrating variable-weight theory, enabling adaptive adjustment of indicator weights according to local ecological conditions. Using Landsat imagery from 2000, 2005, 2010, 2016, 2020, and 2023, the spatiotemporal evolution and spatial heterogeneity of ecological environmental quality were systematically investigated. The results indicate that: (1) ecological environmental quality exhibited a characteristic evolution process of mining disturbance–ecological degradation–comprehensive restoration–ecological recovery during 2000–2023, with an overall trend dominated by stability and improvement; (2) ecological environmental quality showed significant spatial clustering, with High–High clusters mainly distributed in areas with favorable ecological conditions, whereas Low–Low clusters were concentrated in regions strongly affected by mining activities; and (3) compared with the conventional RSEI, the DV-RSEI better characterized mining-related ecological degradation patterns and the spatial heterogeneity of ecological environmental quality. The proposed approach provides a scientific basis for dynamic ecological monitoring, evaluation of ecological restoration effectiveness, and the construction of green mines in ion-adsorption rare earth mining areas. Full article

River regulation creates reservoir shorelines with hydrological regimes that differ from those of adjacent riparian wetlands, but it remains unclear whether wetland setting and geomorphic region are reflected similarly in aggregate community attributes and species composition. We examined plant community attributes, species composition, dominant-species patterns, and their associations with soil and topographic conditions across 20 wetlands in the Han River basin, China. No community attribute differed significantly between riparian and reservoir shoreline wetlands, whereas lowland wetlands had greater plant cover than mountain wetlands. Of the 28 species recorded on reservoir shorelines, 24 also occurred in riparian wetlands. Species composition showed modest differentiation between mountain and lowland wetlands but not between wetland settings, and the ordination showed considerable overlap among groups. Cynodon dactylon dominated all groups, while the frequency and cover of other common species varied spatially. Slope, fine substrate, and distance to water were significantly associated with species composition, but explained a limited proportion of the variation. Slope contributed most within the explained component. These findings indicate that spatial and seasonal variation may be expressed differently across aggregate community attributes and species patterns. Reservoir shoreline assessment may therefore benefit from considering species composition and dominant-species structure alongside vegetation cover and richness. Full article

Climate change and human activities are significantly altering hydrological systems, intensifying extreme events such as hydrological drought patterns. These changes pose critical challenges for water sustainability, requiring a deeper understanding of prolonged hydrological droughts. Under the complex changing environment, hydrological drought in the Upper Yangtze River is becoming increasingly severe. Using monthly scale meteorological and hydrological data, this study quantitatively conducted an attribution analysis of hydrological drought in the Upper Yangtze River through a multi-method framework combining mutation analysis, a hydrological model, and machine learning. The results showed that: (1) the coupled model had higher precision and better applicability in a basin with more complex changing environments. (2) Climate change was the dominant factor for most months of monthly scale hydrological drought in the Wujiang, Jialing, and Upper Yangtze River Basins, while human activities were the main cause of hydrological drought in most months in the Tongtian River. (3) The dominant factor for seasonal hydrological drought in the Wujiang and Upper Yangtze River Basins was climate change. The seasonal hydrological drought in the Tongtian River and Jialing River basins was jointly affected by climate change and human activities. Full article

Structural uncertainty limits the reliability of conceptual hydrological models, yet the effect of pairing runoff-generation and routing structures remains poorly understood. We evaluated 46 models from the Modular Assessment of Rainfall–Runoff Models Toolbox (MARRMoT) in the Xunhe and Hanzhong catchments of the upper Han River Basin and recombined the modules of five representative models into 20 off-diagonal configurations. Validation KGE values for the 46 base models ranged from 0.166 to 0.806 in Xunhe and from 0.043 to 0.830 in Hanzhong. Only M58 and M60 improved KGE in both catchments: M58 increased KGE by 1.68% in Xunhe and 5.98% in Hanzhong, whereas M60 increased it by 5.05% and 3.72%, respectively. Most other recombinations preserved or reduced performance. The improved combinations retained contributions from runoff pathways with different response timescales and showed greater sensitivity to routing parameters; degraded combinations tended to be dominated by groundwater runoff and showed weak routing-parameter sensitivity. These convergent patterns provide indirect evidence that correspondence between runoff composition and routing response may influence recombined-model performance. Because structural compatibility was not measured directly and only two catchments were examined, the proposed relationship requires validation across broader hydroclimatic and structural settings. Full article

Heilongjiang Province, northeastern China, occupies a key metallogenic position between the eastern Central Asian Orogenic Belt and the western Pacific continental margin. This review integrates published geological, geochronological, fluid–inclusion, and H–O–S–Pb isotope data to evaluate tectonic controls on endogenic gold mineralization. Four principal metallogenic episodes are recognized: Caledonian porphyry-related mineralization associated with Paleo–Asian Ocean subduction–accretion; Variscan skarn-forming magmatic–hydrothermal activity; Indosinian post-collisional structurally focused and epithermal hydrothermal activity; and Yanshanian mineralization characterized by Late Jurassic compressional reworking followed by a dominant Cretaceous Paleo–Pacific-related magmatic–hydrothermal pulse. Ore-forming fluids evolved non-monotonically from Paleozoic high-temperature magmatic fluids to more heterogeneous crustal, metamorphic, and meteoric–water–influenced systems. Zhengguang and Laozuoshan provide clear evidence for temporally distinct superimposed mineralization. Later hydrothermal reactivation could either remobilize and reconcentrate Au or leach, disperse, and obscure earlier mineralization. Exploration should therefore prioritize reactivated structural corridors where intrusive centers, reactive wall rocks, volcanic basins, and multi-stage alteration overlap. Full article

In this work, we aim to enhance the photocatalytic performance of SrTiO₃ by constructing a heterojunction with photoactive BiOBr. The novelty of this study lies in demonstrating the dual functionality of the SrTiO₃/BiOBr heterojunction in both photocatalytic tetracycline degradation and antibacterial applications and correlating its performance with its interfacial electronic properties. A SrTiO₃/BiOBr (50STO) heterojunction was successfully synthesized by combining microwave-assisted sol–gel-derived SrTiO₃ with co-precipitated BiOBr via solid-state calcination. XRD analysis revealed that the synthesized composite consisted of crystalline cubic SrTiO₃ and tetragonal BiOBr, confirming the successful formation of a 50STO heterojunction while preserving the crystal structures of both components. PL and EIS analyses revealed modified charge-carrier behavior, further supporting the successful formation of the 50STO heterojunction. XPS confirmed the chemical states of the constituent elements and revealed changes in the surface chemical environment following the coupling of SrTiO₃ with BiOBr. SEM, elemental mapping, and UV–Vis DRS analyses demonstrated uniform elemental distribution, enhanced visible-light absorption, suppressed electron–hole recombination, and improved interfacial charge transfer. Consequently, the optimized 50STO composite achieved 45% tetracycline degradation under visible-light irradiation within 150 min, whereas pristine SrTiO₃ degraded only 2%. The apparent reaction rate constant increased from 6.11 × 10⁻⁷ to 3.2 × 10⁻³ min⁻¹, while the heterojunction remained stable over five reuse cycles. Radical scavenging and LC–MS analyses identified h⁺ and •OH as the dominant reactive species and revealed successive tetracycline degradation. The composite also exhibited excellent antibacterial activity against E. coli under white-light irradiation. Full article

Permian sedimentary manganese carbonate deposits in the Qiling Basin exhibit substantial resource potential, yet their depositional environments and precipitation pathways remain insufficiently constrained. This study integrates petrographic, mineralogical, whole-rock geochemical, and carbonate C–O isotope data from the Shuibutou Mn deposit in southern Hunan. We compare this deposit with the coeval Dongxiangqiao deposit and other Permian marine sedimentary Mn deposits to constrain its depositional setting, Mn-carbonate precipitation mechanisms, and potential Mn sources. The Shuibutou ores contain 10.88–17.18 wt.% MnO and are characterized by spherulitic–oolitic textures, abundant bioclasts, and framboidal pyrite. Mo–U enrichment indicates anoxic bottom waters, whereas the near-marine δ¹³C_carb values of ore carbonates (−0.24‰ to 1.28‰) are consistent with precipitation within a marine carbonate system and suggest direct precipitation of Mn(II) carbonates from dissolved Mn²⁺ under anoxic conditions. In this setting, dissolved Mn²⁺ accumulated below the chemocline. Partial dissolution of platform-derived calcite grains near the chemocline increased local dissolved inorganic carbon and alkalinity, driving Mn-carbonate supersaturation and the authigenic precipitation of manganoan calcite, ultimately forming manganese carbonate ores. The low Al/(Al + Fe + Mn) ratios, high Fe/Ti ratios, and Co–Ni–Zn and REY geochemical characteristics are consistent with a possible contribution from Mn-rich deep fluids to the dissolved Mn²⁺ inventory of the basin waters. Similarities in mineralogy, geochemistry, and depositional setting between Shuibutou and Dongxiangqiao point to a possible regional role for the direct precipitation of Mn(II) carbonates under anoxic conditions in the Middle Permian Qiling Basin. Relatively deep intraplatform basins may therefore represent favorable targets for manganese carbonate exploration and provide a reference for exploration targeting of Permian sedimentary Mn deposits within the Qiling Basin. Full article

Yiyuan jade, a specific gem-quality jade variety in the East Qinling Orogen, occurs as lenticular and vein-shaped bodies hosted within the dolomite and biotite-quartz marble of the Neoproterozoic Meiyaogou Formation. Based on detailed petrological and mineralogical characterization, three subtypes are defined: tremolite jade (nephrite), serpentine jade (a green variety of serpentine group minerals that resembles true jade), and their transitional varieties. Among these, tremolite jade is predominantly white, moon-white, and light green, whereas serpentine jade (gem-quality serpentine) exhibits dark green, yellow-green, and yellow coloration. Comprehensive mineral composition analyses are presented, encompassing amphibole, serpentine, carbonate minerals, and titanite in metagabbro, aiming to constrain the physicochemical conditions and genetic model of these jades. We propose that tremolite jade and serpentine jade are probably formed simultaneously via metasomatic processes, primarily governed by variations in fluid volume and the activities of SiO₂ and CO₂. The serpentine jade is interpreted as serpentinized marble, within which local serpentine aggregation forms serpentine jade akin to Lantian jade in the western East Qinling region. The tremolite jade closely resembles Hetian tremolite jade within geochemical and mineralogical characteristics but differs significantly from serpentine-type tremolite jade associated with ultramafic rocks, thereby confirming its classification as dolomite-type jade. Application of the Ti-in-tremolite geothermometer yields a formation temperature exceeding 400 °C. Integrated with regional geochronological constraints, our findings link the formation of Yiyuan tremolite jade and serpentine jade to tectonic activity driven by the Late Devonian subduction of the Erlangping back-arc basin. This study not only enhances the current understanding of jade mineralization within collisional orogenic settings but also establishes a robust foundation for future exploration in the East Qinling Orogen. Full article