Journal of Hydrology-Regional Studies最新文献_第4页

Machine learning-informed vulnerability assessment of coastal erosion: A case study of the Minjiang River Estuary 基于机器学习的海岸侵蚀脆弱性评估——以闽江河口为例

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-01-20 DOI: 10.1016/j.ejrh.2026.103132

Xiaohe Lai , Ningyuan Xu , Jun Jiang , Jianping Jia , Yan Liu , Yan Su , Chuan Lin , Xiudong Xie , Aijun Wang , Feng Cai

Study region

Minjiang River Estuary, China.

Study focus

Reliable assessments of coastal erosion risk are essential for sustainable urban planning. However, existing methods often fail to capture the dynamic, nonlinear interactions of natural and anthropogenic factors, and the "black-box" nature of many machine learning models limits their practical application. Addressing this gap, we developed a dynamic framework to assess long-term coastal erosion vulnerability in the Minjiang River Estuary. Our study integrated multi-temporal data from 16 key erosion-inducing factors over a 30-year period (1990–2020) and employed five machine learning algorithms to enhance both the predictive accuracy and interpretability of the model.

New hydrological insights for the region

New Hydrological Insights for the Region: Results reveal a generally weak erosion trend along the estuary, punctuated by zones of intense local degradation. The Random Forest model achieved the highest accuracy (≥0.92) and AUC (≥0.97), enabling reliable identification of high-risk areas for targeted coastal management interventions, such as shoreline protection and urban planning adjustments. Feature importance analyses indicate watershed-scale land cover and land use (LCLU) dynamics are the dominant drivers of long-term erosion vulnerability, while short-term patterns are shaped by temporally variable factors. These findings highlight the critical value of integrating time-sensitive drivers into coastal risk assessments and underscore the importance of model selection for adaptive urban and environmental management. The proposed approach offers a scalable and transferable methodology for supporting climate-resilient planning in vulnerable coastal cities.

研究区域：中国闽江口。可靠的海岸侵蚀风险评估对可持续城市规划至关重要。然而，现有的方法往往无法捕捉自然和人为因素的动态、非线性相互作用，许多机器学习模型的“黑箱”性质限制了它们的实际应用。为了解决这一问题，我们开发了一个动态框架来评估闽江河口长期海岸侵蚀脆弱性。我们的研究整合了30年间（1990-2020年）16个关键侵蚀诱导因子的多时间数据，并采用了5种机器学习算法来提高模型的预测准确性和可解释性。该地区的新水文见解：研究结果显示，河口沿岸的侵蚀趋势普遍较弱，偶尔会出现局部严重退化的区域。随机森林模型获得了最高的精度（≥0.92）和AUC(≥0.97)，能够可靠地识别高风险区域，以便进行有针对性的海岸管理干预，如海岸线保护和城市规划调整。特征重要性分析表明，流域尺度土地覆盖和土地利用（LCLU）动态是长期侵蚀脆弱性的主要驱动因素，而短期格局则受时间变量的影响。这些发现突出了将时间敏感驱动因素纳入沿海风险评估的关键价值，并强调了模式选择对适应性城市和环境管理的重要性。拟议的方法为支持脆弱沿海城市的气候适应型规划提供了一种可扩展和可转移的方法。

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引用次数: 0

Cascade reservoirs attenuate the seasonality of estuarine tidal duration asymmetry 梯级水库减弱了河口潮时不对称的季节性

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-01-19 DOI: 10.1016/j.ejrh.2026.103153

Jianliang Lin , Haowei Chen , Xianzhao He , Shuai Hu , Linxi Fu , Huayang Cai , Lixia Niu , Xiaohe Zhang , Xiangyuan Li , Ping Zhang , Qingshu Yang

Study region

The Pearl River Estuary in southern China has strong monsoonal wet-dry discharge contrasts and extensive cascade reservoir regulation in its basin.

Study focus

This study quantifies how reservoir-driven discharge re-partitioning affects the seasonality and multi-decadal evolution of tidal duration asymmetry (TDA; the difference between flood and ebb durations). To reveal the linkage between TDA and regulated discharge, we analyze 51 years (1966–2016) of water levels from 21 tide gauges and daily discharge from three upstream stations using a tidal skewness metric, non-stationary harmonic diagnostics, and trend analysis.

New hydrological insights for the region

TDA shows significant seasonality, with higher skewness in the wet season (April–September) and lower skewness in the dry season (October–March), and a basin-wide trough in late June–early July when discharge peaks. The discharge-TDA relation is threshold-dependent: normalized skewness increases with normalized discharge up to ∼0.62 (∼12,550 m³/s) and decreases thereafter. Reservoir regulation reduced wet-season peak flows (−76.3 m³/s/yr) and increased dry-season baseflows (+16.5 m³/s/yr), attenuating seasonal TDA amplitude most strongly in river–tide transition reaches (−0.0036 /yr). Spatial differences indicate phase-controlled TDA seasonality upstream but amplitude-controlled seasonality downstream, consistent with shifts in dominant tidal interactions from K₁–O₁–M₂ to M₂–M₄. The threshold rule links managed discharge to seasonal TDA and supports basin-to-estuary flow management in regulated coastal rivers.

珠江口流域具有强烈的季风干湿对比和广泛的梯级水库调节。本研究量化了水库驱动的流量再分配如何影响潮汐持续时间不对称（TDA）的季节性和多年代际演变。为了揭示TDA与调节流量之间的联系，我们使用潮汐偏度度量、非平稳谐波诊断和趋势分析，分析了51年（1966-2016）21个潮汐计的水位和三个上游站的日流量。数据显示出明显的季节性特征，雨季（4 - 9月）偏度较高，旱季（10 - 3月）偏度较低，6月下旬- 7月初是流域范围内的波谷，此时流量达到峰值。流量- tda关系是阈值相关的：归一化偏度随着归一化流量的增加而增加，最高可达0.62(~ 12,550 m³/s)，此后减小。水库调节降低了湿季峰值流量（−76.3 m³/s/yr），增加了干季基流量（+16.5 m³/s/yr），对季节TDA振幅的衰减在河潮过渡段最为强烈（−0.0036 /yr）。空间差异表明上游TDA季节性受相位控制，下游TDA季节性受幅度控制，与主导潮汐相互作用从K₁-O₁-M₂向M₂-M₄转变相一致。阈值规则将管理排放与季节性TDA联系起来，并支持受管制的沿海河流的流域到河口流量管理。

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引用次数: 0

Analysis of hydrological drought and TWS-related drivers in Yunnan Province Using GNSS-derived TWS, multi-source hydrological data and the XGBoost model 基于gnss衍生TWS、多源水文数据和XGBoost模型的云南省水文干旱及TWS相关驱动因素分析

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-01-12 DOI: 10.1016/j.ejrh.2026.103120

Yong Su , Zhanjie Qu , Yakun Pu , Qiong Li , Xi Zhang , Ji Feng

Study region

Yunnan Province.

Study focus

Using vertical displacement data from 43 GNSS stations across Yunnan Province, this study first inverted terrestrial water storage anomalies (TWSA) for 2011–2019, then developed the novel GNSS Combined Climatologic Deviation Index (GNSS-CCDI) through integration with precipitation observations, ultimately employing XGBoost modeling to quantify key driving factors.

New hydrological insights for the region

The retrieved TWSA agrees well with GRACE and GLDAS data, yet the latter two underestimate TWSA changes. The GNSS-CCDI is consistent with other drought indices. Five drought events occurred from 2011 to 2019, with the severest starting in July 2011 for 9 months. Main factors influencing TWSA vary across regions, with soil moisture, lake, and snow having the greatest impact in Yunnan.

研究区域：云南省。本研究利用云南省43个GNSS站点的垂直位移数据，首先反演了2011-2019年的陆地蓄水异常（TWSA），然后结合降水观测建立了新的GNSS联合气候偏差指数（GNSS- ccdi），最终利用XGBoost模型量化关键驱动因素。检索到的TWSA与GRACE和GLDAS数据吻合良好，但后两者低估了TWSA的变化。GNSS-CCDI与其他干旱指数基本一致。2011 - 2019年共发生5次干旱事件，最严重的一次发生在2011年7月，持续了9个月。影响TWSA的主要因素在不同地区存在差异，其中对云南的影响最大的是土壤水分、湖泊和积雪。

引用次数: 0

Impacts of urbanization on precipitation and thermodynamic–dynamic mechanisms of typhoon 城市化对降水的影响及台风的热力动力机制

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-02-05 DOI: 10.1016/j.ejrh.2026.103190

Yushan Ma , Kaixin Liu , Qiang Wang , Jie Wang , Chao Gao , Song Song , Yu Xu

Study region

Eastern Zhejiang Province, a highly urbanized coastal region in southeastern China.

Study focus

Urbanization modifies land–atmosphere interactions, yet its influence on rainfall evolution during landfalling tropical cyclones remains unclear. Using Super Typhoon Lekima (2019) as a representative case, this study applies triple-nested WRF simulations to examine urbanization effects on typhoon-induced precipitation under three land-use scenarios: 2001 Urban, 2020 Urban, and 2020 No Urban. Model performance is evaluated using precipitation observations from 236 meteorological stations and best-track data, showing reasonable agreement with a mean track error of 66.64 km and a precipitation correlation coefficient of 0.68.

New hydrological insights for the region

Urbanization induces a stage-dependent rainfall response with spatial heterogeneity. During early landfall, urban areas suppress rainfall by 10–20 mm due to reduced latent heat flux, weakened near-surface moisture availability, and urban-induced dynamic blocking that limits low-level moisture transport. As the storm moves inland, enhanced surface roughness and a “high 2-m air temperature (T₂)–high sensible heat flux (HFX)–low latent heat flux (LH)” energy pattern strengthen instability and convergence, producing 5–10 % higher peak rainfall than the 2001 urban condition. In contrast, natural surfaces sustain higher post-peak rainfall through stronger evapotranspiration and moisture recycling. These findings indicate elevated flood risk during peak stages in urbanized coastal basins and support stage-specific flood risk management in eastern Zhejiang.

研究区域：浙江省东部是中国东南部高度城市化的沿海地区。城市化改变了陆地-大气相互作用，但其对热带气旋登陆期间降雨演变的影响尚不清楚。以超级台风利基玛（2019）为例，采用三套WRF模拟方法，研究了2001年城市、2020年城市和2020年无城市三种土地利用情景下城市化对台风降水的影响。利用236个气象站的降水观测资料和最佳航迹资料对模型性能进行了评价，结果表明，模型的平均航迹误差为66.64 km，降水相关系数为0.68。区域城市化的水文新认识引起了具有空间异质性的阶段依赖的降雨响应。在登陆早期，由于潜热通量减少、近地表水分可用性减弱以及城市诱导的动态阻塞限制了低层水分输送，城市地区抑制了10-20 mm的降雨。随着风暴向内陆移动，增强的地表粗糙度和“高2米气温（T₂）-高感热通量(HFX) -低潜热通量（LH）”的能量模式加强了不稳定性和辐合性，使峰值降雨量比2001年城市状况高5 - %。相比之下，自然地表通过更强的蒸散发和水分再循环来维持更高的峰后降雨量。研究结果表明，沿海城市化盆地洪峰期洪水风险升高，为浙东地区分阶段洪水风险管理提供了依据。

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引用次数: 0

From risk to resilience: Quantifying water security through reliability and robustness analysis with simulation–optimization framework 从风险到弹性：基于仿真优化框架的可靠性和鲁棒性分析量化水安全

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-01-23 DOI: 10.1016/j.ejrh.2026.103144

Chia-Wen Wu , Frederick N.-F. Chou , Dawn Brady

Study Region

Taiwan’s six major municipalities face pronounced wet–dry seasonal contrasts and rely heavily on monsoon-driven inflows to sustain year-round supply. Despite high annual precipitation, the uneven temporal distribution, concentration of storage in a few key reservoirs, and the strong role of agricultural withdrawals create recurrent drought risks. These conditions make the region an effective setting for operationalizing water-security assessment.

Study Focus

Water security has been widely framed from a global or continental perspective, but applying this broad concept to regional-scale drought management requires more operational clarity. This study develops a context-sensitive analytical framework to address this need. Building on Hashimoto’s (1982) concepts, two indicators are formulated—annual reliability based on sector-specific tolerance thresholds and the maximum annual deficit in percent-days. An integrated simulation–optimization model is developed to quantify these indices, explicitly representing policy-driven allocation priorities.

New Hydrological Insights for the Region

Results reveal prototypical spatial patterns: frequent but manageable shortages in the north, rare but severe deficits in central Taiwan, and both frequent and severe events in the south. The framework also identifies conditions under which optimal management fails and quantifies the backup water required for drought resilience in reservoir-dependent regions.

台湾六个主要城市面临着明显的干湿季节差异，严重依赖季风驱动的资金流入来维持全年供应。尽管年降水量高，但时间分布不均匀、主要水库的储水量集中以及农业取水的强烈作用造成了经常性干旱风险。这些条件使该区域成为实施水安全评估的有效环境。研究焦点：水安全已被广泛地从全球或大陆的角度提出，但将这一广泛的概念应用于区域尺度的干旱管理需要更多的操作清晰度。本研究开发了一个上下文敏感的分析框架来满足这一需求。基于Hashimoto（1982）的概念，我们制定了两个指标——基于行业特定公差阈值的年度可靠性和以百分比天为单位的最大年度赤字。建立了一个综合仿真优化模型来量化这些指标，明确表示政策驱动的分配优先级。结果揭示了典型的空间格局：北部频繁但可控的缺水，中部罕见但严重的缺水，南部既频繁又严重。该框架还确定了最佳管理失效的条件，并量化了依赖水库地区抗旱所需的备用水。

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引用次数: 0

Characterizing spatially concurrent hydrological drought and its response to meteorological drought under the impact of human activities 人类活动影响下空间同步水文干旱特征及其对气象干旱的响应

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-01-14 DOI: 10.1016/j.ejrh.2026.103129

Shaokun He , Qianxun Li , Kebing Chen , Lingling Zhu

Study region

The study region is the upper Hanjiang River Basin in China.

Study focus

Understanding how spatially concurrent hydrological droughts (HD) respond to meteorological droughts (MD) is crucial for early drought warning and mitigation, yet such assessments remain limited under human-altered conditions. This study examines two sub-regions (S1 and S2) in the upper Hanjiang River Basin using monthly precipitation and streamflow data (1961–2020) to characterize the inter-regional MD–HD linkages through elementary and Copula functions.

New hydrological insights for the region

Results indicate that during the natural pre-change period, both S1 and S2 exhibited strong elementary functional relationships between MD and HD magnitudes (R² > 0.8). When the MD magnitude of S1 reached a threshold of 1.16, HD onset occurred, and the HD magnitude of S2 fell within a 70 % probability interval of [0.58, 3.16] with a most likely value of 0.70. In the post-change period, human interventions—particularly reservoir regulation and irrigation—disrupted these elementary linkages, yielding more complex non-linear propagation patterns. The Copula framework successfully quantified the probabilistic linkage of concurrent HDs across regions, enabling estimation of HD severity in one basin based on MD information from another. These findings provide quantitative insight into cross-regional drought propagation and offer practical implications for hydrological drought monitoring and management in data-scarce or regulated basins.

研究区域研究区域为中国汉江上游流域。研究重点：了解空间同步水文干旱（HD）如何响应气象干旱（MD）对于早期干旱预警和缓解至关重要，但在人为改变的条件下，此类评估仍然有限。本研究利用1961-2020年汉江上游的月降水和流量数据，通过初等函数和Copula函数表征了区域间的MD-HD联系。结果表明，在自然变化前，S1和S2在MD和HD震级之间表现出较强的初等函数关系（R2 > 0.8）。当S1的MD震级达到1.16阈值时，HD发生，S2的HD震级在70 %的概率区间内[0.58,3.16]，最可能值为0.70。在变化后的时期，人类干预，特别是水库调节和灌溉，破坏了这些基本的联系，产生了更复杂的非线性传播模式。Copula框架成功地量化了不同地区并发HD的概率联系，从而可以根据来自另一个盆地的MD信息来估计HD的严重程度。这些发现提供了对跨区域干旱传播的定量见解，并为数据稀缺或受管制的流域的水文干旱监测和管理提供了实际意义。

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引用次数: 0

Driving mechanisms and nonlinear responses of ecological drought in Northern China's Agro-Pastoral Ecotone 中国北方农牧交错带生态干旱驱动机制及非线性响应

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-01-27 DOI: 10.1016/j.ejrh.2026.103174

Yaoyuan Fan , Jian Zhang , Asim Biswas , Siyi Cheng , Xiaoran Ren , Chunhui Zhan

Study region

Northern China's Agro-Pastoral Ecotone (APENC, 2000–2022) was selected as a climatically sensitive transition belt from semi-arid to semi-humid conditions.

Study focus

We developed a kernel Temperature–Vegetation Dryness Index (kTVDI) that exploits the kernel Normalized Difference Vegetation Index to overcome spectral saturation, and coupled it with XGBoost–SHAP and Generalized Additive Models to decode nonlinear drought drivers. Validated against an independent soil moisture dataset, kTVDI demonstrated superior sensitivity (ρ = −0.604 vs. −0.533 for TVDI) and stronger agreement with solar-induced chlorophyll fluorescence (SIF), supporting its use as an improved ecological drought indicator. Over 2000–2022 regional drought declined significantly (–1.328 × 10⁻³ yr⁻¹, p < 0.01), but spatial heterogeneity persisted: south-eastern alleviation vs. north-western intensification.

New hydrological insights for the region

Temperature universally dominates (32.92–52.24 % SHAP importance), yet land-use/land-cover restructures secondary controls: vegetated systems exhibit evapotranspiration-regulated water balance, whereas deserts display precipitation-limited dynamics amplified by human disturbance. Critical thresholds marking energy–water regime shifts are 6.6 °C for temperature, 387 mm yr⁻¹ for evapotranspiration and 54.2 % for relative humidity. Interaction analysis further reveals land-use-specific synergies (humidity–soil in croplands, soil–topography in forests, topography–precipitation–human activity in deserts), underscoring ecosystem-dependent vulnerability. This interpretable framework advances process-based drought understanding in ecotones and furnishes quantitative thresholds for adaptive management under global change.

研究区选择中国北方农牧交错带（APENC, 2000-2022）作为半干旱到半湿润气候敏感过渡带。利用核归一化植被指数克服光谱饱和，建立了核温度-植被干燥指数（kTVDI），并将其与XGBoost-SHAP和广义加性模型相结合，解码非线性干旱驱动因素。通过独立的土壤湿度数据集验证，kTVDI表现出更高的灵敏度（ρ = - 0.604 vs. TVDI的- 0.533），并且与太阳诱导的叶绿素荧光（SIF）更一致，支持其作为改进的生态干旱指标。2000-2022年期间，区域干旱显著减少（-1.328 × 10⁻³yr⁻¹，p <； 0.01），但空间差异持续存在：东南缓解与西北加剧。温度普遍占主导地位（32.92-52.24 % SHAP重要性），但土地利用/土地覆盖重构了次要控制因素：植被系统表现出蒸散调节的水分平衡，而沙漠表现出受人类干扰放大的降水限制动态。标志着能量-水状态转变的临界阈值是：温度6.6°C，蒸散量387 mm yr⁻¹ ，相对湿度54.2% %。相互作用分析进一步揭示了特定土地利用的协同作用（农田中的湿度-土壤、森林中的土壤-地形、沙漠中的地形-降水-人类活动），强调了依赖生态系统的脆弱性。这一可解释的框架促进了过渡带中基于过程的干旱理解，并为全球变化下的适应性管理提供了定量阈值。

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引用次数: 0

Synergistic architecture of conventional GRACE filters: Global generality to region-specific optimal filtering via multiscale hydrologic validation 传统GRACE过滤器的协同结构：通过多尺度水文验证的区域特定优化过滤的全球一般性

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-01-27 DOI: 10.1016/j.ejrh.2026.103180

Xiaohui Wu, Yunlong Wu, Sulan Liu, Qi Liu, Danyi Hu

Study region

This study is global in scope, providing a framework with regional applicability. We validate the methodology across 40 river basins and Lakes Victoria and Nasser, ensuring broad relevance under diverse hydrological conditions.

Study focus

This study aims to evaluate the performance of traditional spatial-domain decorrelation filters at the basin scale. We proposed a collaborative filtering framework to integrate and enhance filter stability while addressing the boundary issues inherent in conventional filters. We summarized the operational principles of the collaborative filter and provided filtering recommendations across different latitudes, offering more robust solutions for small-scale regions.

New hydrological insights for the region

Our analysis reveals that the synergistic architecture effectively overcomes boundary effects inherent in traditional filters through a latitude-dependent strategy. The proposed YAV mode is critical for low-latitude regions, effectively mitigating high-frequency striping noise to recover masked tropical signals and enable the monitoring of small-scale lakes. Conversely, the SAY and SAV modes ensure signal stability in mid-to-high latitudes by avoiding leakage. Quantitative results demonstrate that this framework improves the proportion of high signal-to-noise ratio results by 10 %–15 % in noise-prone areas. Ultimately, this approach enhances the detection of extreme hydrological events and offers a robust, extendable baseline for future gravity missions.

本研究的范围是全球性的，提供了一个具有区域适用性的框架。我们在40个流域以及维多利亚湖和纳赛尔湖验证了该方法，确保了在不同水文条件下的广泛相关性。本研究旨在评价传统的空域去相关滤波器在流域尺度下的性能。我们提出了一个协同过滤框架来整合和增强过滤稳定性，同时解决传统过滤器固有的边界问题。我们总结了协同过滤的工作原理，并提供了跨不同纬度的过滤建议，为小规模地区提供了更强大的解决方案。我们的分析表明，通过依赖纬度的策略，协同结构有效地克服了传统过滤器固有的边界效应。所提出的YAV模式对于低纬度地区至关重要，它可以有效地减轻高频条纹噪声，以恢复被掩盖的热带信号，并使小尺度湖泊的监测成为可能。相反，SAY和SAV模式通过避免泄漏来确保信号在中高纬度地区的稳定性。定量结果表明，该框架将噪声易发区域的高信噪比结果的比例提高了10 % -15 %。最终，这种方法增强了对极端水文事件的检测，并为未来的重力任务提供了一个强大的、可扩展的基线。

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引用次数: 0

Isotopic composition (δ18O, δ2H) of the Indian Summer Monsoon in Southern Oman: A model-aided process interpretation 阿曼南部印度夏季风的同位素组成（δ18O, δ2H）：一个模式辅助过程解释

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-02-04 DOI: 10.1016/j.ejrh.2026.103172

Thomas Müller , Robert van Geldern , Jan Friesen , Mark Schmidt , Ali Bakhit Ali Bait Said , Kay Knöller , Nils Michelsen

Study region

This study deals with the isotopic composition of monsoon precipitation in Southern Oman, specifically in the Salalah coastal plain and the adjacent Dhofar Mountains.

Study focus

Monsoon variability on the southern Arabian Peninsula has been described based on the oxygen isotope composition of various terrestrial archives, often on the millennial scale. However, the factors influencing the spatio-temporal variability of the oxygen isotope composition of today's monsoon precipitation have not yet been described for this region. Here, we present stable isotope ratios of oxygen and hydrogen for the Indian Summer Monsoon in the greater Salalah area.

New hydrological insights for the region

The precipitation amount-weighted mean isotope values along an elevation transect show lighter signatures at higher elevation, but generally low deuterium excess values (d<10 ‰). To trace the origin and (short-term) history of the precipitation system, we applied a 3-step model incorporating evaporation of seawater, condensation, and sub-cloud evaporation. Our modelling exercise indicates that the classic elevation effect is quasi-negligible, and that sub-cloud evaporation is likely to be the main driver behind the encountered isotope pattern. This pseudo-elevation effect implies that the precipitation is not depleted in heavy isotopes with increasing elevation, but rather enriched with decreasing elevation. This effect may prevail in other (semi-arid) areas as well.

本研究研究了阿曼南部季风降水的同位素组成，特别是在Salalah沿海平原和邻近的佐法尔山脉。研究重点：根据各种陆地档案的氧同位素组成，通常在千年尺度上描述了阿拉伯半岛南部的季风变率。然而，影响该地区现今季风降水氧同位素组成时空变异的因素尚未被描述。在这里，我们给出了大塞拉莱地区印度夏季风的氧和氢的稳定同位素比率。沿高程样带的降水量加权平均同位素值在高海拔处表现出较轻的特征，但总体上较低的氘过量值（d<10 ‰）。为了追踪降水系统的起源和（短期）历史，我们采用了一个包含海水蒸发、凝结和次云蒸发的三步模式。我们的模拟工作表明，经典的海拔效应几乎可以忽略不计，云下蒸发可能是所遇到的同位素模式背后的主要驱动因素。这种伪海拔效应表明，降水中的重同位素不是随着海拔的增加而减少，而是随着海拔的降低而增加。这种效应在其他（半干旱）地区也可能普遍存在。

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引用次数: 0

Reconstruction of global long-term daily streamflow dataset using machine learning models for revealing streamflow changes 利用机器学习模型重建全球长期日流量数据集，揭示流量变化

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-04-01 Epub Date: 2026-01-19 DOI: 10.1016/j.ejrh.2026.103148

Yingying Gao , Zengliang Luo , Huan Liu , Lunche Wang , Xi Chen , Huan Li

Study regions

314 major global watersheds.

Study focus

In the context of widespread streamflow observation data gaps and significant basin heterogeneity worldwide, this study aims to construct a high-precision, long-term global daily-scale streamflow reconstruction dataset. Focusing on 314 major river basins globally (1980–2020), we systematically evaluate the performance of four machine learning models—Random Forest (RF), Gradient Boosting Decision Tree (GBDT), Extreme Gradient Boosting (XGBoost), and Light Gradient Boosting Machine (LightGBM)—in reconstructing streamflow sequences and identify optimal modeling strategies suitable for different basin conditions. To reduce input data uncertainty, the study concentrates on reconstructing streamflow at basin outlets, leveraging their larger catchment areas and relatively reliable meteorological forcing information. The resulting dataset provides a high-quality resource for analyzing global streamflow variability and its climatic drivers.

New hydrological insights for the region

Based on the reconstructed dataset, a study of long-term streamflow patterns in global river basins, with a focus on the changing characteristics of extreme flows (high and low flows) and their climatic drivers, reveals the following: African river basins show the highest proportion of significant increasing trends in both long-term and extreme streamflow; South America and Australia have a relatively large number of river basins (approximately 58 % and 59 %, respectively) where long-term streamflow shows a significant decrease. Globally, the proportion of river basins with significantly increasing mid- to long-term streamflow is generally below 10 %, while a higher proportion of basins show rising trends in low flows and mean flows, reflecting a possible trend toward wetter conditions in most regions. Additionally, ENSO plays an important regulatory role in streamflow variability, particularly in tropical regions, where El Niño and La Niña events correspond to significant alternating dry and wet anomalies in streamflow responses.

研究区域314个全球主要流域。在全球范围内广泛存在的河流观测数据缺口和明显的流域异质性背景下，本研究旨在构建高精度、长期的全球日尺度河流重建数据集。以1980-2020年全球314个主要河流流域为研究对象，系统评估了随机森林（RF）、梯度增强决策树（GBDT）、极端梯度增强（XGBoost）和光梯度增强机（LightGBM）四种机器学习模型在重建河流序列中的性能，并确定了适合不同流域条件的最佳建模策略。为了减少输入数据的不确定性，研究集中在流域出水口重建水流，利用其更大的集水区和相对可靠的气象强迫信息。由此产生的数据集为分析全球流量变率及其气候驱动因素提供了高质量的资源。基于重建数据集，对全球河流流域的长期流量模式进行了研究，重点研究了极端流量（高流量和低流量）的变化特征及其气候驱动因素，结果表明：非洲流域的长期和极端流量都呈现出显著增加趋势的比例最高；南美洲和澳大利亚有相对较多的流域（分别约为58% %和59% %），其中长期流量显着减少。在全球范围内，中长期流量显著增加的流域比例一般在10% %以下，而较高比例的流域在低流量和平均流量方面呈上升趋势，反映了大多数地区可能的湿润趋势。此外，ENSO在径流变率中起着重要的调节作用，特别是在热带地区，El Niño和La Niña事件对应于径流响应中显著的干湿交替异常。

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