Journal of Hydrology-Regional Studies最新文献_第8页

Quantifying rainfall variability and potential hazards of extreme events in Beijing through stochastic simulations 基于随机模拟的北京极端事件降水变率及其潜在危害

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-06 DOI: 10.1016/j.ejrh.2025.103068

Tinghui Li , Shuiqing Yin , Yuanyuan Xiao , Maoqing Wang , Liutong Chen , Wenyue Zou , Nadav Peleg

Study region

The city of Beijing, China.

Study focus

Beijing is affected by heavy rainfall in summer, which may trigger urban floods. These risks make long rainfall records valuable for extreme rainfall analysis, given the complex spatiotemporal patterns and high natural variability of rainfall; however, such records are unavailable. To address this limitation, we propose using a gridded rainfall generator capable of capturing natural climate variability and enabling the simulation of yet-unobserved extreme rainfall events. The AWE-GEN-2d was used to extend the rainfall sample by simulating 30 realizations of 30 years each at 1 km and hourly intervals based on steady-state climate assumptions. It was calibrated and validated with weather stations, local high-resolution gridded rainfall estimates, and the Merra-2 climate reanalysis product. We then analyzed the natural variability and extreme characteristics of rainfall based on the stochastically generated data.

New hydrological insights for the region

Rainfall variability increases with higher spatiotemporal resolution and peaks at the event-based level. For extreme events, variability grows markedly with longer return periods, and rainfall amounts for the 100-year return period can exceed station records by up to 53 % through event-based IDF curves. This study emphasizes the heterogeneity of rainfall fields and reveals the hazards of yet-unobserved extreme rainfall events under a stationary climate, providing critical insights for improving urban flood management strategies in highly urbanized regions like Beijing.

研究区域：中国北京市。北京夏季受强降雨影响，这可能引发城市洪水。考虑到复杂的时空模式和高度的自然变率，这些风险使得长期降雨记录对极端降雨分析有价值；然而，这样的记录是不可用的。为了解决这一限制，我们建议使用能够捕获自然气候变率的网格降雨发生器，并能够模拟尚未观测到的极端降雨事件。基于稳态气候假设，awwe - gen -2d通过模拟30年的30个实现，每个实现以1 km和每小时的间隔来扩展降雨样本。它通过气象站、当地高分辨率网格化降雨估计和Merra-2气候再分析产品进行校准和验证。然后，我们基于随机生成的数据分析了降雨的自然变率和极端特征。降雨变率随时空分辨率的提高而增加，并在基于事件的水平上达到峰值。对于极端事件，变率随着回归期的延长而显著增加，通过基于事件的IDF曲线，100年回归期的降雨量可超过台站记录高达53 %。本研究强调了降雨场的异质性，揭示了固定气候条件下未观测到的极端降雨事件的危害，为改善北京等高度城市化地区的城市洪水管理策略提供了重要见解。

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引用次数: 0

Climate and land use change driving divergent surface water dynamics in the Northern China agro-pastoral ecotone 气候和土地利用变化驱动中国北方农牧交错带地表水动态差异

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-06 DOI: 10.1016/j.ejrh.2025.103098

Jie LIAN , Yulin LI , Xuyang WANG , Yanqing LI , Yicheng ZHANG , Jing FENG , Na SU , Yuqiang LI

Study region

Northern China’s agro-pastoral ecotone (APE), a semi-arid to semi-humid transitional zone encompassing five major watersheds: Songhua River Basin (SHB), Liaohe River Basin (LB), Haihe River Basin (HB), Yellow River Basin (YB), and Inner Mongolia Endorheic Basin (EB).

Study focus

We integrated high-resolution surface water datasets with hydro-meteorological products and land use records to assess impacts on net water yield (NWY). Analysis of surface water dynamics (areas > 1 ha) was conducted using Theil-Sen slope estimation and structural equation modeling.

New hydrological insights

The APE experienced marginally significant hydrological aridification during 1986–2020, characterized by net surface water loss (-4140 ha yr⁻¹, p = 0.052) and declining water body numbers (-158.7 yr⁻¹, p = 0.092). Watershed trends exhibited pronounced divergence, with the most severe depletion in the LB (-1523 ha yr⁻¹ and −55.7 water bodies yr⁻¹) and moderate declines in the EB (-716 ha yr⁻¹ and −7.2 yr⁻¹), contrasting sharply with significant expansion in the YB (1169 ha yr⁻¹ and 46.2 yr⁻¹, p < 0.001). Major lakes/reservoirs underwent a significant shrinkage, with relative water area (RWA) declining at −1.22 % yr⁻¹ (p < 0.05) and the maximum shrinkage rate in the LB (-3.29 % yr⁻¹, p < 0.001). A declining aridity index and intensified land use, particularly irrigation expansion and revegetation, amplified evapotranspiration (ET), with cropland areas since 2000 showing average ET increases of 1.9 ± 2.6 mm yr⁻¹ (GLEAM) and 6.5 ± 2.5 mm yr⁻¹ (MODIS), thereby diminishing NWY across the APE. These divergent watershed trajectories demonstrate that anthropogenic interventions have outweighed climatic drivers to reconfigure surface water distribution. This human-mediated redistribution of water resources necessitates watershed-specific allocation frameworks to secure regional water sustainability.

研究区域：中国北方农牧交带（APE），一个半干旱半湿润过渡带，包括五大流域：松花江流域（SHB）、辽河流域（LB）、海河流域（HB）、黄河流域（YB）和内蒙古内河流域（EB）。我们将高分辨率地表水数据集与水文气象产品和土地利用记录相结合，以评估对净水量（NWY）的影响。地表水动力学分析（区域>； 1 ha）采用Theil-Sen坡度估计和结构方程建模。在1986-2020年期间，APE经历了边际显著的水文干旱化，其特征是净地表水损失（-4140 ha yr -1, p = 0.052）和水体数量减少（-158.7 yr -1, p = 0.092）。流域趋势表现出明显的差异，最严重的是LB （-1523 ha yr -1和- 55.7水体yr -1）的枯竭，而EB （-716 ha yr -1和- 7.2 yr -1）的中度下降，与YB（1169 ha yr -1和46.2 yr -1, p <； 0.001）的显著扩张形成鲜明对比。主要湖泊/水库发生了显著的收缩，相对水面积（RWA）下降了- 1.22 % yr - 1 (p <； 0.05)，最大收缩率在LB（-3.29 % yr - 1, p <； 0.001）。干旱指数的下降和土地利用的强化，特别是灌溉扩张和植被恢复，增加了蒸散量（ET），自2000年以来，耕地面积的平均蒸散量增加了1.9 ± 2.6 mm yr - 1 （GLEAM）和6.5 ± 2.5 mm yr - 1 (MODIS)，从而减少了整个APE的NWY。这些不同的流域轨迹表明，在重新配置地表水分布方面，人为干预超过了气候驱动因素。这种以人为中介的水资源再分配需要针对流域的分配框架，以确保区域水资源的可持续性。

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引用次数: 0

A parallel attention-based framework for multi-step multivariate runoff forecasting in mountainous watersheds: Wuyuan case study 基于并行关注的山地流域多步多元径流预测框架——以婺源为例

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-06 DOI: 10.1016/j.ejrh.2025.103045

Jiange Jiang , Chen Chen , Yang Zhou , Wei Han , Lei Liu , Qingqi Pei

Study region:

Wuyuan County, Jiangxi Province, China

Study focus:

To address the challenges of multivariate modeling and error accumulation in multi-step runoff forecasting, we propose a Parallel Attention Multivariate Multi-step LSTM Network (PAM²-LSTM). This framework integrates parallel subnetworks to capture heterogeneous relationships between hydrological variables and combines direct multi-step forecasting with attention mechanisms to mitigate error propagation. The model was evaluated on high-resolution observational data from Wuyuan.

New hydrological insights for the region:

The PAM²-LSTM significantly outperforms conventional LSTM and other baseline models, achieving a 70.5% improvement in MAE and a 61.2% reduction in RMSE for 6-hour ahead forecasts. The model maintains robust accuracy across extended prediction horizons, with Nash–Sutcliffe Efficiency (NSE) values exceeding 0.97 for 6 h. Visualization of results confirms precise temporal alignment with observed hydrographs and reliable peak flow estimation, critical for flash flood warning systems. The parallel architecture’s superior performance highlights its capability to leverage multivariate data while minimizing cumulative errors, offering a reliable tool for flood risk management in complex mountainous watersheds.

研究重点：为解决多步径流预测中多变量建模和误差积累的问题，提出了一种平行关注多步LSTM网络（PAM2-LSTM）。该框架集成了并行子网，以捕获水文变量之间的异质关系，并将直接多步预测与注意机制相结合，以减轻误差传播。利用婺源的高分辨率观测资料对模型进行了评价。PAM2-LSTM显著优于传统的LSTM和其他基线模型，在提前6小时预测中，MAE提高了70.5%，RMSE降低了61.2%。该模型在扩展的预测范围内保持了强大的准确性，NSE值在6小时内超过0.97。结果的可视化证实了与观测到的水文和可靠的峰值流量估算的精确时间一致性，这对山洪预警系统至关重要。并行架构的卓越性能突出了其利用多元数据的能力，同时最大限度地减少累积误差，为复杂山区流域的洪水风险管理提供了可靠的工具。

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引用次数: 0

Separating flow components in tile drainage and streamflow in a headwater agricultural catchment 农业水源集水区水系与水系的分离

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-06 DOI: 10.1016/j.ejrh.2025.103081

Larissa Gospodyn , Helen Jarvie , Mark Williams , Janina Plach , Merrin Macrae

Study Region

This study was conducted in a headwater, tile-drained, agricultural catchment in southern Ontario, under a typical cropping system in the Great Lakes Region.

Study Focus

Hydrograph separation has become a common approach to infer water sources and nutrient pathways to stream discharge but is less frequently used to separate tile drain effluent. The identification of hydrologic and nutrient pathways into both streams and tiles is important in agricultural management and modelling. We separated ten event hydrographs for one contributing tile and stream outlet site over a one-year period using two graphically-based approaches and a mass balance approach using a variety of common geochemical tracers.

New Hydrological Insights for the Region

Few studies to date have examined the application of various hydrological separation techniques in tile discharge across a range of hydrometric conditions. Although methods differed in their operational definition of baseflow, we observed similar baseflow estimates across differing methods during wet, spring conditions and diverging estimates were found for snowmelt periods. When calibrating a graphically-based method with tracers, the resulting hydrographs became less flashy with smaller peak baseflow amounts compared to the tracer-based separation alone and is therefore not recommended when intra-event dynamics are of importance. Findings show that electrical conductivity can be successfully used in headwater agricultural streams and tile drainage discharge to separate flow components, but sampling additional tracers during critical periods, such as snowmelt or following fertilizer application, is recommended to ensure the most appropriate tracers and adequate end-member representation is acquired.

研究区域本研究是在安大略省南部的一个源头，瓦片排水，农业集水区进行的，在一个典型的种植制度下，在大湖区。研究重点：水图分离已成为推断水源和水流排放的营养途径的常用方法，但很少用于分离排水废水。确定进入河流和河流的水文和营养途径对农业管理和建模很重要。我们使用两种基于图形的方法和使用各种常见地球化学示踪剂的质量平衡方法，在一年的时间内分离了一个贡献瓦和溪流出口地点的十个事件水文。迄今为止，很少有研究考察了各种水文分离技术在一系列水文条件下的瓦片排放中的应用。尽管不同方法对基流的操作定义不同，但我们观察到，在湿润和春季条件下，不同方法的基流估计相似，而融雪期的基流估计存在差异。当使用示踪剂校准基于图形的方法时，与单独基于示踪剂的分离相比，所得的水文图变得不那么花哨，峰基流量更小，因此在事件内动力学很重要时不推荐使用。研究结果表明，电导率可以成功地用于水源农业溪流和排水排放，以分离流动成分，但建议在关键时期（如融雪或施肥后）取样额外的示踪剂，以确保获得最合适的示踪剂和充分的端元代表性。

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引用次数: 0

Spatiotemporal changes of the water conservation function in the six major river basins in Yunnan Province, Southwest China 云南省六大流域水源涵养功能的时空变化

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-06 DOI: 10.1016/j.ejrh.2025.103073

Honglei Tang , Yunhao Lai , Cun Zhan , Zheng Lu , Qihua Ran

Study region

Six major river basins in the mountainous Southwest China.

Study focus

Patterns and drivers of water conservation in mountainous regions with heterogeneous environments remain poorly understood. In this study, we explored spatiotemporal dynamics of water conservation in the six basins from 2000 to 2023. The InVEST model was used to simulate water yield, with trend and variability analyses characterizing temporal and spatial patterns. Correlation analysis further evaluated the roles of climate, soil, vegetation, and human activities.

New hydrological insights for the region

The results showed that the average annual water conservation was lowest in the Jinsha River basin (78.02 mm) and highest in the Irrawaddy River basin (241.24 mm). Most regions exhibited declining trends in water conservation mainly due to increasing potential evapotranspiration, while the downstream Jinsha River basin and parts of the Pearl River basin showed increasing trends due to increasing precipitation. The water conservation coefficient (WCC) was more sensitive than the water conservation volume in detecting ecosystem degradation. The Pearl River basin experienced the most significant urban expansion, while the Irrawaddy River basin showed the most severe net forest loss, both of which weakened water conservation capacity as reflected by WCC. This study provides valuable scientific guidance for region-specific ecological planning and water resource management in the southwest China.

研究区域中国西南山区六大河流流域。研究重点：山地异质环境下水资源保护的模式和驱动因素尚不清楚。研究了2000 - 2023年6个流域的水土保持时空动态。利用InVEST模型模拟水量，并进行趋势和变率分析，分析其时空格局特征。相关分析进一步评价了气候、土壤、植被和人类活动的作用。结果表明：金沙江流域年平均保水量最低（78.02 mm），伊洛瓦底江流域最高（241.24 mm）；由于潜在蒸散量的增加，大部分地区的保水能力呈下降趋势，而下游的金沙江流域和部分珠江流域由于降水的增加，保水能力呈上升趋势。水涵养系数（WCC）比保水体积对生态系统退化的检测更为敏感。珠江流域的城市扩张最为显著，而伊洛瓦底江流域的森林净损失最为严重，两者都削弱了WCC所反映的保水能力。该研究为西南地区的区域生态规划和水资源管理提供了有价值的科学指导。

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引用次数: 0

Assessing the risk of extreme precipitation in Japan through GEV distribution and spatial modeling 基于GEV分布和空间模拟的日本极端降水风险评估

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-06 DOI: 10.1016/j.ejrh.2026.103107

Zhichao Jiao , Jihui Yuan , Craig Farnham , Kazuo Emura

Study region

Japan, characterized by diverse climatic zones and complex topography, has experienced increasing frequency and severity of extreme precipitation events in recent decades. Rural areas, in particular, face heightened flood risks due to sparse meteorological observation networks and challenges in implementing uniform design standards across complex terrains.

Study focus

This study analyzed hourly precipitation data from 752 meteorological stations across Japan (1981–2020). First, return levels were calculated for each station using the Generalized Extreme Value (GEV) distribution. Subsequently, the INLA-SPDE method, incorporating covariates such as annual precipitation and distance to the coastline, was employed to spatially predict extreme precipitation in unobserved areas. The predictive accuracy and stability were rigorously compared with ordinary kriging interpolation.

New hydrological insights for the region

The INLA-SPDE method outperformed kriging in predictive stability, yielding significantly smaller standard deviations for long return periods. Results reveal that spatial variability intensifies with extreme levels: while precipitation intensity generally decreases from south to north, a notable northward expansion of high-risk zones was observed for 50- and 100-year return periods. Specifically, localized extremes emerged in southern Hokkaido and parts of Tohoku, regions traditionally considered lower risk. These findings highlight the limitations of current hazard maps and provide a robust scientific basis for updating hydrological management strategies under climate change. These findings contribute to improved understanding of regional precipitation extremes and provide a scientific basis for flood risk assessment, hydrological management, and disaster prevention planning in Japan.

研究区日本气候多样，地形复杂，近几十年来极端降水事件的发生频率和严重程度都有所增加。特别是农村地区，由于气象观测网稀疏，以及在复杂地形上实施统一设计标准的挑战，面临着更大的洪水风险。本研究分析了日本752个气象站（1981-2020）的逐时降水数据。首先，利用广义极值（GEV）分布计算各站点的回波水平。随后，采用INLA-SPDE方法，结合年降水量和到海岸线距离等协变量，对未观测区域的极端降水进行空间预测。与普通克里格插值的预测精度和稳定性进行了严格比较。INLA-SPDE方法在预测稳定性方面优于克里格法，在较长的回归周期内产生明显较小的标准差。结果表明，在极端水平上，空间变异性增强：降水强度总体上由南向北减小，50年和100年回归期的高发区显著向北扩展。具体来说，局部极端天气出现在北海道南部和东北部分地区，这些地区传统上被认为风险较低。这些发现突出了当前灾害图的局限性，并为在气候变化下更新水文管理战略提供了坚实的科学基础。这些发现有助于提高对区域极端降水的认识，并为日本洪水风险评估、水文管理和防灾规划提供科学依据。

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引用次数: 0

Assessing future hydrologic extremes using an integrated hydrology and river operations model in the Russian River watershed 在俄罗斯河流域使用综合水文和河流运行模型评估未来的水文极端情况

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-06 DOI: 10.1016/j.ejrh.2025.103016

Saalem Adera , Ayman Alzraiee , Richard Niswonger , Enrique Triana , Derek Ryter , John Engott

Study region

The Russian River watershed, situated in coastal, northern California, experiences hydrologic extremes, including periodic droughts and flooding. Water managers are working to maintain sustainable water supplies and environmental flows, while mitigating flood risks.

Study focus

This paper introduces an integrated hydrology and river operations model for the Russian River watershed. This model is distinct from models in previous studies because it represents surface-groundwater interactions and uses climate forcings to estimate dynamic water use demands that are superimposed onto both reservoir operations and water supply constraints. The model was used to examine three historical (1990–2015) and eight future (2016–2099) water use and climate change scenarios.

New hydrological insights for the region

The direct connection between streams and aquifers facilitated both annual aquifer replenishment by high winter streamflows and streamflow depletion by groundwater wells (19 % of pumped groundwater in alluvial aquifers from stream leakage) during critical low flow periods. Simulated streamflow changes included 59 % longer and 54 % more severe streamflow droughts, 26 % lower seasonal low streamflows, and up to 125 % higher peak streamflows, averaged over future climate and water use scenarios, suggesting increased future flood and water availability risks. Results showed the importance of reservoir operations for mitigating the impacts of increased hydroclimatic volatility, despite a decrease in reservoir reliability at Lake Mendocino, suggesting that reservoir management may be used to decrease future risks.

研究区域位于加利福尼亚北部沿海地区的俄罗斯河流域，经历了包括周期性干旱和洪水在内的极端水文现象。水管理人员正在努力维持可持续的水供应和环境流动，同时减轻洪水风险。本文介绍了俄罗斯河流域水文与河流综合运行模型。该模型不同于以往研究中的模型，因为它代表了地表水与地下水的相互作用，并利用气候强迫来估计叠加在水库运行和供水约束上的动态用水需求。该模型用于考察三个历史情景（1990-2015年）和八个未来情景（2016-2099年）的水资源利用和气候变化。河流和含水层之间的直接联系促进了冬季高流量的年度含水层补充和地下水井的枯竭（19 %的冲积含水层抽水地下水来自河流泄漏）在关键的低流量时期。在未来气候和水资源利用情景下，模拟的流量变化包括：干旱时间延长59 %，严重程度增加54 %，季节性低流量减少26 %，峰值流量增加125 %，表明未来洪水和水资源可利用性风险增加。结果表明，尽管Mendocino湖的水库可靠性有所下降，但水库运营对于减轻水文气候波动性增加的影响至关重要，这表明水库管理可以用来降低未来的风险。

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引用次数: 0

Assessment of potential drought hazard in Gansu Province under climate change 气候变化下甘肃省潜在干旱灾害评价

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-05 DOI: 10.1016/j.ejrh.2025.103093

Sha Zhao , Haoyan Zhang , Yanzhe Sun , Yansheng Liu , Yaowen Xie

Study Region

Gansu Province, Northwestern China.

Study Focus

Accurate prediction of drought evolution is crucial to promote climate change adaptation capabilities. This study evaluated drought evolution during the near-future (2020–2060) and far-future (2061–2100) and explored ecosystem responses under the SSP2–4.5 and SSP5–8.5. In addition, we proposed a new drought hazard index (DHI) that incorporates drought dynamics to assess drought hazard.

New Hydrogeological Insights from the Region

Droughts are expected to intensify relative to historical conditions, with SSP5–8.5 showing stronger drought trends, while SSP2–4.5 shows more frequent and prolonged droughts. The drought instantaneous recovery speed (IRS) is forecasted to accelerate across all climate scenarios, with the greatest increase in SSP5–8.5, while the instantaneous development speed (IDS) shows a significant rise only under SSP5–8.5. Forests and croplands exhibited relatively lower drought intensity and faster IRS, whereas grasslands, urban, and bare land experienced more frequent and prolonged droughts with slower IRS. Moreover, the responses of IDS and IRS to climatic factors vary among ecosystems, with the IRS of vegetation showing particularly high sensitivity to variations in precipitation and temperature. The results also indicate that the drought hazard level in the northwestern area will further increase in the future, whereas it shows a decreasing trend in the central area. Although the drought hazard level in the southwestern region is relatively low, it is gradually increasing.

研究区域：中国西北部的甘肃省。研究重点准确预测干旱演变对提高适应气候变化能力至关重要。本研究评估了近未来（2020-2060年）和远未来（2061-2100年）的干旱演变，探讨了SSP2-4.5和SSP5-8.5下的生态系统响应。此外，我们还提出了一种新的干旱危险指数（DHI），该指数结合了干旱动态来评估干旱危险。相对于历史条件，SSP5-8.5表现出更强的干旱趋势，而SSP2-4.5表现出更频繁和更长时间的干旱。预测干旱瞬时恢复速度（IRS）在各气候情景下均呈加速趋势，其中SSP5-8.5情景下增幅最大，而瞬时发展速度（IDS）仅在SSP5-8.5情景下显著上升。森林和农田表现出相对较低的干旱强度和较快的IRS，而草地、城市和裸地则表现出较频繁和持续的干旱，IRS较慢。此外，不同生态系统的IDS和IRS对气候因子的响应存在差异，植被的IRS对降水和温度的变化表现出特别高的敏感性。结果还表明，未来西北地区的干旱灾害程度将进一步增加，而中部地区的干旱灾害程度将呈下降趋势。西南地区干旱危险度虽相对较低，但呈逐渐上升趋势。

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引用次数: 0

The evolution of drought characteristics in semi-arid Africa over the last four decades 过去四十年半干旱非洲干旱特征的演变

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-05 DOI: 10.1016/j.ejrh.2025.103087

Komi Mawulom Claude Afamondji , Alyson Brayner Sousa Estacio , Ismail Mohsine , Nourelhouda Karmouda , Tarik Bouramtane , Mounia Tahiri , Ilias Kacimi , Sarah Tweed , Marc Leblanc

Study region

Semi-arid Africa, covering six subregions: the Mediterranean (MED), Sahel, North Eastern Africa (NEAF), South Eastern Africa (SEAF), Southern Africa (SAF), and Madagascar (MDG).

Study focus

We analyse drought duration, intensity, and severity from 1979 to 2024 across semi-arid Africa. Using Climate Prediction Center (CPC, 0.5°) precipitation and temperature, we compute the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). Trends are detected with the Mann–Kendall test and Theil–Sen slope estimator. Short-term droughts (3–6 months), strongly influenced by temperature variability, are distinguished from 12-month events driven by cumulative hydrological deficits.

New hydrological insights

Three drought episodes emerge: the early 1990s, early 2000s, and the recent period beginning in 2022. Long time-scale indices (SPI-12, SPEI-12) capture the most persistent droughts, whereas short time-scale indices (SPEI-3, SPEI-6) reveal intense temperature-driven episodes. In MED, only 7–25 % of grid cells show significant SPI trends in duration, severity, and intensity, but up to 75 % exhibit drought intensification with SPEI, underscoring strong temperature sensitivity. Across NEAF, SEAF, SAF, and MDG, 25–55 % of pixels show significant increases in drought duration (up to +3 months per decade), severity (+3 units per decade), and intensity (+0.5 units per decade). Parts of the western Sahel and southern Madagascar display decreasing trends. Overall, the study delivers a continent-wide assessment of drought evolution and identifies hotspots where intensifying drought threatens water resources and food security.

研究区域半干旱非洲，包括六个分区域：地中海（MED）、萨赫勒、东北部非洲（NEAF）、东南部非洲（SEAF）、南部非洲（SAF）和马达加斯加（MDG）。研究重点分析了1979年至2024年非洲半干旱地区干旱的持续时间、强度和严重程度。利用气候预测中心（CPC, 0.5°）降水和温度，计算了标准化降水指数（SPI）和标准化降水蒸散指数（SPEI）。趋势是通过Mann-Kendall检验和Theil-Sen斜率估计来检测的。受温度变率强烈影响的短期干旱（3-6个月）不同于由累积水文亏缺驱动的12个月干旱。新的水文见解出现了三次干旱：20世纪90年代初、21世纪初和最近从2022年开始的时期。长时间尺度指数（SPEI-12、SPEI-12）反映了最持久的干旱，而短时间尺度指数（SPEI-3、SPEI-6）反映了强烈的温度驱动事件。在MED中，只有7 - 25% %的网格细胞在持续时间、严重程度和强度上表现出显著的SPI趋势，但高达75% %的网格细胞在SPEI中表现出干旱加剧，强调了强烈的温度敏感性。在NEAF、SEAF、SAF和千年发展目标中，25 - 55% %的像素显示干旱持续时间（每十年+3个月）、严重程度（每十年+3个单位）和强度（每十年+0.5个单位）显著增加。萨赫勒西部和马达加斯加南部部分地区呈现下降趋势。总体而言，该研究对整个大陆的干旱演变进行了评估，并确定了干旱加剧威胁水资源和粮食安全的热点地区。

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引用次数: 0

Evaluating the impact of elevated CO2 on the hydrological cycle and carbon budgets in the loess plateau 黄土高原二氧化碳浓度升高对水文循环和碳收支的影响

IF 5 2区地球科学 Q1 WATER RESOURCES

Journal of Hydrology-Regional Studies

Pub Date : 2026-01-05 DOI: 10.1016/j.ejrh.2026.103104

Bowen Zhu , Xianhong Xie , Yi Yao , Xuehua Zhao

Study region

Loess Plateau (LP), China

Study focus

Understanding the impact of elevated CO₂ (eCO2) concentrations on water-carbon interactions is critical for informing climate mitigation strategies in semi-arid regions susceptible to hydrological stress. Although CO₂ fertilization effects on terrestrial processes are well documented, existing models often oversimplify land cover heterogeneity and neglect region-specific feedbacks, limiting their applicability to complex landscapes like the LP. This study addresses these limitations by employing the Community Land Model (CLM5), which represents diverse land types, including forests, grasslands, and croplands (such as corn and wheat), and is validated against flux tower and remote sensing data.

New hydrological insights for the region

This work reveals that eCO2 nearly doubles gross primary productivity by 2.78 gC/m²/yr, while suppressing evapotranspiration by 1.42 mm/yr and increasing baseflow by 1.09 mm/yr. Despite vegetation carbon gains (∼19.16 gC/m²/yr), soil organic carbon exhibited a continued decline at 6.01 gC/m²/yr, suggesting slower soil carbon recovery. Water use efficiency (WUE) improved disproportionately, with forests exhibiting a 50 % increase due to deep-rooted systems and stomatal optimization, and croplands showing only a 10 % improvement, likely constrained by irrigation practices. Spatial heterogeneity emerged as a dominant control, with the marginal gain in WUE per unit increase in CO₂ (WUE/CO₂ ratio) declined by 14 % over two decades, highlighting water constraints in semi-arid ecosystems. By integrating land cover-specific responses, this study advances the homogenized CO₂ representations in land surface models and offers actionable insights for targeting afforestation in ecological restoration zones. These findings highlight the necessity of resolving spatial heterogeneity in Earth system models to enhance climate adaptation strategies and optimize water-carbon synergies under escalating CO₂ scenarios.

研究重点：了解二氧化碳（eCO2）浓度升高对水-碳相互作用的影响，对易受水文压力影响的半干旱区提供气候缓解策略至关重要。虽然CO 2施肥对陆地过程的影响已被充分记录，但现有模型往往过于简化土地覆盖异质性，忽视了区域特定的反馈，限制了它们对LP等复杂景观的适用性。本研究通过采用社区土地模型（CLM5）解决了这些局限性，该模型代表了不同的土地类型，包括森林、草地和农田（如玉米和小麦），并针对通量塔和遥感数据进行了验证。这项工作表明，eCO2使总初级生产力增加了近一倍，增加了2.78 gC/m²/年，同时抑制了1.42 mm/年的蒸散，增加了1.09 mm/年的基流。尽管植被碳增加（~ 19.16 gC/m²/yr），但土壤有机碳持续下降，为6.01 gC/m²/yr，表明土壤碳恢复较慢。水分利用效率（WUE）显著提高，由于深层根系系统和气孔优化，森林的WUE提高了50% %，而农田的WUE仅提高了10% %，这可能受到灌溉方式的限制。空间异质性成为主要控制因素，20年来单位CO₂增加的WUE边际收益（WUE/CO₂比率）下降了14% %，突出了半干旱生态系统的水资源限制。通过整合土地覆被特异性响应，本研究推进了地表模型中CO₂的均一化表示，并为生态恢复区造林提供了可操作的见解。这些发现强调了解决地球系统模型空间异质性的必要性，以加强气候适应策略并优化CO₂不断上升情景下的水-碳协同效应。

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引用次数: 0