Journal of Hydrology最新文献

{"title":"Unraveling river-tide process connectivity in complex deltaic networks","authors":"Yajun Wang ,&nbsp;Jianliang Lin ,&nbsp;Yu Yan ,&nbsp;Shuxian Wang ,&nbsp;Zhenyan She ,&nbsp;Chengyu Jin ,&nbsp;Kairong Lin ,&nbsp;Tongtiegang Zhao ,&nbsp;Giovanni Coco ,&nbsp;Huayang Cai","doi":"10.1016/j.jhydrol.2025.134301","DOIUrl":"10.1016/j.jhydrol.2025.134301","url":null,"abstract":"<div><div>The Pearl River Delta (PRD) is one of the world’s most complex deltaic systems, shaped by the dynamic interaction between river discharge and tidal forces. However, the mechanisms governing river-tide connectivity within this system remain unclear, particularly with respect to the nonlinear feedback processes and spatiotemporal lag effects. This study employs an information-theoretic framework to investigate process connectivity in the PRD, integrating relative mutual information and relative transfer entropy to quantify synchrony, causality, and directional information flow among river discharge, tides, and water levels. The results reveal that river discharge predominantly governs water level synchrony in the upper PRD, while tidal dynamics exert stronger causal effects downstream water levels. Since the 1990s, human interventions have weakened the influence of river discharge, while tidal impacts have remained relatively stable. Furthermore, water level connectivity is modulated by seasonal and tidal cycles, with discharge effects dominating during flood seasons and tidal forces prevailing during dry seasons, particularly under spring tide conditions. By integrating time-lag effects, our framework reveals delayed yet physically consistent driver-response pathways and refines the spatial structure of hydrodynamic connectivity. This work presents the first lag-aware, information-theoretic quantification of river-tide connectivity in a complex deltaic system. These insights, constituting the first lag-aware, information-theoretic quantification of river-tide connectivity in a complex delta, enhance our understanding of deltaic hydrodynamics and provide a stronger basis for hydrodynamic modeling, adaptive management, and resilience planning in deltas.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134301"},"PeriodicalIF":6.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A graph neural network using physical attributes to improve the system-wide nodal water-level prediction in sparsely monitored urban drainage systems","authors":"Li He ,&nbsp;Jun Nan ,&nbsp;Xuesong Ye ,&nbsp;Lei Chen ,&nbsp;Shasha Ji ,&nbsp;Zewei Chen ,&nbsp;Qiliang Xiao","doi":"10.1016/j.jhydrol.2025.134306","DOIUrl":"10.1016/j.jhydrol.2025.134306","url":null,"abstract":"<div><div>Nodal water levels are a critical hydraulic parameter indicative of the operational status of urban drainage networks (UDNs), and their system-wide sensing is essential for evaluating system capacity and promptly identifying urban flooding and overflow pollution risks. However, due to financial constraints and installation challenges, the widespread deployment of sensors in UDNs is impractical. While developing approaches based on graph neural networks for system-wide sensing and prediction in sparsely monitored drainage systems is an effective solution, methods that rely solely on simple topological connectivity exhibit instability and significant prediction errors due to the complex and variable flow conditions within UDNs, influenced by multiple uncertainties. To address this challenge, we propose an edge-attribute-enhanced spatiotemporal graph convolutional network (Edge-STGCN) to improve prediction accuracy in sparsely monitored UDNs, offer a novel perspective to evaluate sensor placement strategies in different branches, and analyze the predictive utility of individual and combined edge attributes for model performance. Results revealed that with only 10% of nodes monitored, the Edge-STGCN model achieved reliable predictions at 88.6% of system-wide nodes, significantly outperforming the multilayer perceptron (14.5%) and STGCN (47.0%). Pipes near the outfall, particularly small-diameter branches whose invert elevations were higher than those of the main trunk pipes, were especially prone to uncertainty in prediction accuracy. Pipe invert elevation was an important contributor to the model’s prediction accuracy. The proposed method enables reliable predictions, informs sensor placement strategies, and provides data support for decision-making aimed at mitigating flooding and pollution.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134306"},"PeriodicalIF":6.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Managing climate water stress: A multi-year analysis from the American Southwest","authors":"Saleh Idhirij ,&nbsp;Frank A. Ward","doi":"10.1016/j.jhydrol.2025.134308","DOIUrl":"10.1016/j.jhydrol.2025.134308","url":null,"abstract":"<div><div>Climate-driven water stress and prolonged drought are intensifying competition between agricultural and urban users in arid regions worldwide. Rising populations and economic activity place mounting pressure on traditional water allocation methods, which often struggle to balance efficiency, equity, and sustainability. While prior research has examined future water demand and compared institutional approaches such as proportional shortage sharing and market-based transfers, few studies have designed and validated hydroeconomic models capable of guiding least-cost adaptation strategies at the basin scale under severe competition. Our study develops and applies a novel hydroeconomic optimization model to evaluate two alternative shortage-sharing mechanisms—unrestricted water trading and proportional sharing —using the Rio Grande Basin in the American Southwest as a case study. Simulations over a four-year period show that proportional reductions impose uniform cutbacks of 30%, while unrestricted trading reallocates water from farms to cities with cash compensation, significantly reducing economic damages across sectors. Findings demonstrate the efficiency gains of market-based institutions in reallocating water during shortages and provide actionable policy insights on water market design, investment timing, and institutional reform to enhance resilience in drought-prone basins.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134308"},"PeriodicalIF":6.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling for conceptualisation and management of coastal plain aquifers under the risks of global change and deep thermal waters","authors":"Shubham Tiwari ,&nbsp;Giuseppe Cianflone ,&nbsp;Giovanni Vespasiano ,&nbsp;Rocco Dominici ,&nbsp;Gianpietro Imbrogno ,&nbsp;Rosanna De Rosa ,&nbsp;Maurizio Polemio","doi":"10.1016/j.jhydrol.2025.134295","DOIUrl":"10.1016/j.jhydrol.2025.134295","url":null,"abstract":"<div><div>Climate change and land use transitions intensify groundwater management challenges in coastal aquifers, where natural recharge is declining and irrigation demand is rising. These pressures are further compounded by deep thermal groundwater upflow, which alters aquifer temperature, salinity, and density-driven flow. This study presents a comprehensive approach finalised to the numerical assessment of the Gioia Tauro coastal aquifer system (southern Italy), which is affected by global change and geogenic thermal water contributions. A variable-density groundwater flow model was developed using SEAWAT, informed by hydrogeological data, land use mapping, and future climate projections. The conceptual model of the aquifer was validated and used to quantify the effects of thermal water upflow and projected climate impacts on groundwater dynamics. The model included steady-state simulations (1950–2000) to represent past conditions and calibrate the system, followed by transient simulations for predictive scenarios through 2100. Results quantify the deep thermal inflow, contributing ∼4.35 % of total groundwater inflow, raising salinity and temperature in fault-controlled zones. By 2100, effective rainfall is expected to decline by 21 %, resulting in a 0.3 m average decline in hydraulic heads and a 76.5 % increase in salinity within the shallow aquifer. These findings highlight the compounded effects of climate variability, land use intensification, and thermal water intrusion on coastal groundwater systems and the proposed approach’s effectiveness in assessing deep thermal flow yield and its salinity and thermal effects. This study underscores the need for integrated, adaptive management strategies to mitigate aquifer depletion and salinisation in similar coastal settings worldwide.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134295"},"PeriodicalIF":6.3,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Water exchange and hydrodynamic responses to multi-phase restoration of tidal flat in Luanhe river estuary","authors":"Yinyi Li ,&nbsp;Baolong Zhang ,&nbsp;Zhe Huang ,&nbsp;Gang Wang ,&nbsp;Haijue Xu ,&nbsp;Yuchuan Bai","doi":"10.1016/j.jhydrol.2025.134299","DOIUrl":"10.1016/j.jhydrol.2025.134299","url":null,"abstract":"<div><div>The tidal flat restoration has been carried out to reconstruct the natural habitats from large-scale aquaculture reclamations in the Luanhe River Estuary. However, the impacts of the project on water exchange has not yet been fully established, which further limits the understanding of the environmental diffusion in the estuary. This study aims to investigate the evolution of hydrodynamics and water exchange due to multi-phase restoration projects, from the perspective of water age. The results indicate that the riverine discharge provides more dominance than the tidal flow in this typical micro-tidal estuary. The discharge directly determines the intensity of water exchange, while the tidal flow only cause minimal fluctuations in the water age. The first-phase restoration projection widens the river channel to facilitate the interaction between riverine discharge and tidal flow. The implementation of the restoration decreases the water age, indicating an enhancement in the water exchange process. This effect is particularly noticeable during the dry season when the riverine discharge is weaker to restrict the water exchange, as evidenced by a 5.8% and 16.3% increase in lower water age area in the flood and dry seasons, respectively. The upstream flow of tidal currents is strengthened by the restoration to significantly improve the exchange intensity of runoff and tide. The evaluation of multi-phase projects show that the spatial layout of the restoration also makes diverse effectiveness. In such a weak tidal estuary, the restoration significantly changed the runoff, can effectively promote water exchange by improving the interaction between runoff and tide with the area of lower water age increasing by 51.1%. On the contrary, the improvement of water exchange by seaside restoration is limited with the area of lower water age increasing by only 9.6%. While, thorough restoration is crucial to further enhance the water exchange process for a long term. The results can provide valuable insights for the planning and implementation of future restoration to achieve greater ecological benefits.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134299"},"PeriodicalIF":6.3,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GIS-based evaluation of advanced supervised learning methods for groundwater spring potential modeling","authors":"Xia Zhao ,&nbsp;Wei Chen ,&nbsp;Paraskevas Tsangaratos ,&nbsp;Ioanna Ilia ,&nbsp;Enke Hou","doi":"10.1016/j.jhydrol.2025.134296","DOIUrl":"10.1016/j.jhydrol.2025.134296","url":null,"abstract":"<div><div>Groundwater, a critical resource for environmental sustainability and socio-economic development, is spatially governed by geological, topographic, and climatic factors. This study developed a GIS-based groundwater spring potential modeling method in the Zhangjiamao area, China, based on the transition zone between the Loess Plateau and the desert. By integrating 93 spring data and 12 multi-source heterogeneous factors, including terrain, hydrology, geology, and landuse data, the predictive performance of six supervised learning models Quadratic Discriminant Analysis (QDA), Linear Discriminant Analysis (LDA), Fisher’s Linear Discriminant Analysis (FLDA), Fuzzy Unordered Rule Induction Algorithm (FURIA), Random Forest (RF), and Bayesian Network (BN) was systematically compared, and corresponding groundwater spring potential zoning maps for the Zhangjiamao area were generated. Factor selection involved multicollinearity diagnostics, correlation analysis, and importance ranking. The most influential factors were distance to rivers (MDA = 8.83), elevation (MDA = 7.44), slope angle (MDA = 6.19), and lithology (MDA = 6.73). Models’ validation showed that all models performed well (AUC &gt; 0.8), with the RF model performing best with AUC values of 0.904 (training) and 0.969 (validation). The standard errors were relatively small (0.0295/training, 0.0192/validation), indicating stable and reliable results. This study clarifies the mechanism of spring potential formation under geohydrological coupling, and offers a methodological framework to support sustainable groundwater development and management in arid and semi-arid areas.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134296"},"PeriodicalIF":6.3,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of declining rainfall and ocean forcing on morphology and dynamics of an island fresh groundwater lens, South-West Western Australia","authors":"S. Sharifazari ,&nbsp;J. McCallum ,&nbsp;K. Meredith ,&nbsp;F. Johnson ,&nbsp;J.G. Palmer ,&nbsp;C.S.M. Turney ,&nbsp;M.S. Andersen","doi":"10.1016/j.jhydrol.2025.134294","DOIUrl":"10.1016/j.jhydrol.2025.134294","url":null,"abstract":"<div><div>Fresh groundwater lenses are an important natural source of potable water for communities on small oceanic islands but are highly vulnerable to climate variability and long-term trends such as prolonged decadal rainfall decline. This is particularly true of the islands along the coast of Southwest-Western Australia located in the Indian Ocean where substantial rainfall declines are the primary driver of a reduction in the volume of groundwater recharge. On these islands, the impact of these changes is further complicated by seawater mixing associated with sea level fluctuations operating on time scales ranging from hourly to seasonal, interannual, and decadal. The complex interaction between climatic and sea level variability highlights the need for well-constrained density-dependent groundwater models to understand changes to recharge on various timescales to manage groundwater resources. This study focused on Rottnest Island where groundwater age data was combined with water level and salinity measurements to develop a 3D density-dependent groundwater model. The steady state modelling of the fresh groundwater lens suggests a recharge rate of −41 % of the long-term historic annual rainfall, with the winter rainfall important for lens recharge, suppressing the upward movement of the saline transition zone groundwater associated with seasonal sea level fluctuations. A transient simulation reveals a substantial reduction of up to 50 % in the volume of potable groundwater (i.e. in the freshwater lens) in response to the prolonged rainfall decline that started in the late 1960s combined with groundwater abstraction. The sustained regional winter rainfall decline experienced in the Southwest Australia region accounts for most of this reduction when considering transient sea level boundary conditions. The modelling approach used in this study for Rottnest Island offers insights that can be applied to other oceanic islands experiencing changing climatic forcings, particularly in regions where sea level variability plays a significant role.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134294"},"PeriodicalIF":6.3,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Natural organic matter drives iodine biogeochemical cycling in multi-layered redox dynamic groundwater systems","authors":"Xingtao Liu ,&nbsp;Xianjun Xie ,&nbsp;Junxia Li ,&nbsp;Yanlong Li ,&nbsp;Kun Qian ,&nbsp;Kunfu Pi ,&nbsp;Yanxin Wang","doi":"10.1016/j.jhydrol.2025.134253","DOIUrl":"10.1016/j.jhydrol.2025.134253","url":null,"abstract":"<div><div>The iodine (I) enrichment of groundwater is observed under wide redox conditions that are controlled by complex hydro-biogeochemical processes. However, the dominant processes across different redox gradients remain unclear. In this study, a field site having a high I concentration was selected, and multi-level monitoring wells [20 m × 30 m × 40 m × 50 m (depth)] were established. The groundwater chemistry was determined, and organic matter (OM) fluorescence and molecular analyses, as well as metagenomics analyses, were performed to identify the dominant biogeochemical processes controlling I enrichment in groundwater. In suboxic environments, phenolic and saturated hydrocarbon-rich aromatic OM provided energy for nitrogen-fixing and dehalogenating microbes, facilitating I desorption from Fe-NOM complexes. Degradation products, such as small organic acids, supported nitrate reduction (narL, narBHY, and nirS) and iodide formation. Under anoxic conditions, <em>Desulfovibrio</em> and dissimilatory sulfate reduction (aprAB and dsrAB) enhanced I enrichment through desorption, deiodination, and reduction, supported by pathways involving saturated and aliphatic compounds. Under strictly anoxic conditions, fermentative bacteria decomposed complex OM, promoting Fe-NOM dissolution and supplying substrates for iron-reducing bacteria, leading to extensive I release. Adsorption by secondary iron sulfides and methylation by methyltransferases (mtrABC and mtaA) partially restricted I concentrations. This study presents a theoretical model that clarifies microbial I mobilization mechanisms in groundwater, highlighting OM degradation prioritization as a key constraint.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134253"},"PeriodicalIF":6.3,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term variations and regional disparities in baseflow during 1960–2021 across China","authors":"Yufen He ,&nbsp;Hanbo Yang ,&nbsp;Changming Li","doi":"10.1016/j.jhydrol.2025.134297","DOIUrl":"10.1016/j.jhydrol.2025.134297","url":null,"abstract":"<div><div>Baseflow (<em>Q</em>_b), the slow-release component of streamflow, plays a vital role in sustaining river ecosystems and water supply during dry periods. However, its long-term spatial and temporal dynamics remain poorly understood across China. This study presents the first nation-scale investigation of baseflow variations across 288 Chinese catchments from 1960 to 2021. We initially evaluated seven widely used baseflow separation methods and identified the Eckhardt method performs best in most (91 %) catchments. Results reveal a distinct south-to-north decline in mean annual <em>Q</em>_b with averaging 317 mm in the south and 54 mm in the north. The proportion of baseflow to streamflow (BFI) increases from southeast to northwest (0.10–0.83), while the proportion of baseflow to precipitation (BFC) shows an increasing gradient from northeast to southwest (0–0.80). Significant intensification of spatial heterogeneity along the 1200 mm isohyet is observed, with northern catchments experiencing a decrease in <em>Q</em>_b and southern catchments showing an increase. Intra-annual <em>Q</em>_b distribution becomes more uniform in 59.0 % catchments. Meanwhile, BFI increases in 68.8 % catchments, highlighting growing baseflow contributions, while BFC declines in 60.0 % catchments, indicating reduced groundwater recharge and potential depletion risks. The key controls on <em>Q</em>_b include precipitation, soil and vegetation in humid catchments, and snow fraction and temperature in arid catchments; and rainfall regimes and topographic factors play significant roles in both partitions (BFI and BFC). These findings provide a comprehensive understanding of the spatial distribution and long-term trends of baseflow, and offer insights for evaluating climate change impacts on groundwater-surface water interactions, as well as guiding basin-specific water management strategies across China.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134297"},"PeriodicalIF":6.3,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel spatiotemporal analysis of snow cover pattern over Finland based on ERA5-land reanalysis","authors":"Ramin Faal,&nbsp;Mojtaba Saboori,&nbsp;Epari Ritesh Patro,&nbsp;Pertti Ala-Aho,&nbsp;Ali Torabi Haghighi","doi":"10.1016/j.jhydrol.2025.134264","DOIUrl":"10.1016/j.jhydrol.2025.134264","url":null,"abstract":"<div><div>As global temperatures rise due to climate change, snow-covered areas in high-latitude regions such as Finland exhibit increasing variability. Variations in Arctic snow cover can significantly impact the ecosystem, hydrological cycle, biodiversity, and many other physical processes. Consistent and detailed assessments of long-term changes in relevant snow cover pattern (SCP) features, including timing of snow accumulation and melt (phenology), duration of snow cover, and the number of snow-free days are crucial for understanding the regional dynamics of the water resources. This study aims to analyze the time series of SCP features in ERA5-Land reanalysis data for Finland. Prevalent SCP assessments exclude critical SCP features, such as the day of the year when maximum snow cover extent in each pixel start and end, which are essential for a thorough spatiotemporal analysis. This study addresses these gaps by analyzing four SCP features in each pixel: the snow onset date, first day of maximum snow cover extent, last day of maximum snow cover extent, and last day of snow cover. Based on ERA5-Land data from 2000 to 2020 and a novel method using convolution kernels and Hadamard-product-based weighting combined with K-means clustering, Finland was clustered into four distinct snow regions based on SCP features. In the largest cluster (114,738 km²) the duration of maximum snow cover extent (D_max) was 189 days of the total 220 days of snow cover duration (D_total). Conversely, the smallest cluster in southern and coastal areas covering 41,630 km², experienced D_max of 85 within 123 days of D_total. Mann-Kendall trend analysis revealed a significant extension of springtime snow cover in northern Finland, while southern and coastal areas experienced reduced winter snow-cover durations. Using K-nearest neighbours method and based on the mentioned four clusters, the 20 annual SCP features images of Finland were classified. The effect of air temperature and precipitation in the annual classification’s results and SCP variability in each region were also investigated. In this regard, we quantified the deviations of SCP form their cluster centroid during snow accumulation period, the period with maximum snow cover extent, and snowmelt period. The classification of annual SCP variations further demonstrated relationships between SCP dynamics and variations in air temperature and precipitation. SCP is particularly susceptible to near-zero air temperature fluctuations, whose effects can be further amplified by precipitation anomalies.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134264"},"PeriodicalIF":6.3,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}