HERA: a high-resolution pan-European hydrological reanalysis (1950–2020)

Published: Feb. 19, 2024

Abstract. Since 1950, European rivers have been put under increasing pressure by anthropogenic activities, resulting in changes climate, land cover, soil properties and channel morphologies. These evolving environmental conditions can translate into hydrological conditions. The availability of consistent estimates river flow at global continental level is a necessity to assess attribute the cycle. To overcome limitations posed observations (incomplete records, inhomogeneous spatial coverage), we simulate discharge for Europe period 1950–2020 using state-of-the-art modelling approach. We use new set up LISFLOOD model, running 1 arcminute (≈1.8 km) with six-hourly time steps. model forced climate reanalysis data (ERA5-land) bias-corrected downscaled resolution weather observations. also ingests 72 surface fields maps representing catchment morphology, vegetation, properties, use, water demand, lakes reservoirs. Inputs related human activities are through emulate society. Hydrological ReAnalysis (HERA), provides 282 521 pixels upstream area > 100 km2. its skill 2901 gauging stations distributed across Europe. Overall, HERA delivers satisfying results, general weak underestimation observed mean variability. find that performance increases between 1950 2020. fine temporal result an enhanced compared other small-to-medium-scale catchments (100–10 000 km2), degraded remaining small catchments. first long-term, high-resolution Despite limitations, it enables analysis dynamics extremes, influences, change scale while keeping local relevance. It creates opportunity study these ungauged

Language: Английский

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Flood Frequency Analysis in West Africa

Journal of Flood Risk Management, Journal Year: 2025, Volume and Issue: 18(1)

Published: Jan. 17, 2025

ABSTRACT Devastating flood events are recurrently impacting West Africa. To mitigate impacts and reduce the vulnerability of populations, a better knowledge on frequency these is crucial. The lack reliable hydrometric datasets has hitherto been major limitation in analysis at scale Utilising recently developed African database, we perform annual maximum flow (AMF) time series, covering 246 river basins Africa, between 1975 2018. Generalized extreme value (GEV) Gumbel probability distributions were compared to fit AMF series with L‐moments, Maximum Likelihood (MLE) (GMLE) methods. Results indicated that GEV distribution GMLE method provided best results. Regional envelope curves entire region unprecedented data coverage have generated for first‐time providing insights estimation quantiles ungauged basins. correlation watershed properties shows significant correlations catchment area, groundwater storage, altitude topographic wetness index. findings from this study useful risk assessment design hydraulic infrastructures region, first step prior development regional approaches transfer information gauged sites catchments.

Language: Английский

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Understanding Flood and Drought Extremes Under a Changing Climate in the Blue Nile Basin: A review

Environmental and Sustainability Indicators, Journal Year: 2025, Volume and Issue: unknown, P. 100638 - 100638

Published: Feb. 1, 2025

Language: Английский

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Wavelet transform-based trend analysis of streamflow and precipitation in Upper Blue Nile River basin

Journal of Hydrology Regional Studies, Journal Year: 2022, Volume and Issue: 44, P. 101251 - 101251

Published: Oct. 26, 2022

Upper Blue Nile River Basin, Ethiopia This study aims to determine possible trends in monthly, seasonal and annual precipitation streamflow series. The Discrete Wavelet Transform (DWT) was used obtain detailed information about the time-frequency conditions of six meteorological five stations during 1984–2014. Mann-Kendall test also applied original DWT components which periodicities are dominant reproducing observed trends. combined has not been explored UBNRB context. We three criteria a suitable wavelet, decomposition level, signal extension mode. From these criteria, bias ratio between wavelet approximation series time proposed this study. Results show that almost all experience an insignificant but increasing trend, whereas exhibit trend at 5% significance level. use periodic events up 4 years more influential affecting

Language: Английский

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Spatiotemporal Application of the Standardized Precipitation Index (SPI) in the Eastern Mediterranean

Climate, Journal Year: 2023, Volume and Issue: 11(5), P. 95 - 95

Published: April 28, 2023

The ever-increasing need for water, the alteration in climate, and its observed changes over recent years have triggered a lot of research studies associated with phenomenon drought. Within wider geographical region Mediterranean, relevant scientific subject seems to be great interest, since it is undoubtedly related number severe socio-economic consequences. This present effort focuses on evolution this particular time, within borders nine different countries Eastern Mediterranean (Athens, Greece—Europe; Constantinople, Turkey—Asia; Nicosia, Cyprus—Europe; Jerusalem, Israel—Asia; Amman, Jordan—Asia; Damascus, Syria—Asia; Beirut, Lebanon—Asia; Cairo, Egypt—Africa; Tripoli Libya—Africa). By applying Standard Precipitation Index (SPI), examining precipitation data at month level (January 1901 December 2020), utilizing Inverse Distance Weighted (IDW) method, spatio–temporal variability drought events area was studied. In long-term droughts presented higher than usual volume, accordance 12- 24-month SPI, starting from mid-20th century. Similarly, Damascus similar pattern those Jerusalem. An upward trend frequency extreme last thirty years. same true terms duration dry periods. Drought also been central, southern, eastern regions Turkey. A downward Cairo based analysis monthly precipitation.

Language: Английский

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Historical climate impact attribution of changes in river flow and sediment loads at selected gauging stations in the Nile basin

Climatic Change, Journal Year: 2024, Volume and Issue: 177(3)

Published: Feb. 26, 2024

Abstract The Nile basin is the second largest in Africa and one of regions experiencing high climatic diversity with variability precipitation deteriorating water resources. As climate change affecting most hydroclimatic variables across world, this study assesses whether historical changes river flow sediment loads at selected gauges can be attributed to change. An impact attribution approach employed by constraining a process-based model set factual counterfactual forcing data for 69 years (1951–2019), from setup Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3a). To quantify role change, we use non-parametric Mann-Kendall test identify trends calculate differences long-term mean annual load simulations between using data. Results stations Lake Victoria show reasonable evidence increase flows (two stations) (one station), largely climate. In contrast, within Blue Main basins, there slight decrease four under climate, which but no significant station). These findings spatial impacts on area period.

Language: Английский

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Variability in flood frequency in Sub-Saharan Africa: The role of large-scale climate modes of variability and their future impacts

Journal of Hydrology, Journal Year: 2024, Volume and Issue: 640, P. 131679 - 131679

Published: July 14, 2024

Sub-Saharan Africa (SSA) is strongly affected by flood hazards, endangering human lives and economic stability. However, the role of internal climate modes variability in driving fluctuations SSA occurrence remains poorly documented understood. To address this gap, we quantify relative combined contribution large-scale drivers to seasonal regional using a new 65-year daily streamflow dataset, sea-surface temperatures derived from observations, 12 Single Model Initial-condition Large Ensembles (SMILEs) Coupled Intercomparison Project Phases 5 6. We find significant relationships between floods across SSA, with climatic accounting for 30–90 % floods. Notably, western, central, summer-rain region southern display stronger teleconnections comparison East winter-rain South Africa, where circulation patterns activities may play more important role. In eastern are mainly influenced Pacific Indian Oceans, while western central Atlantic Ocean Mediterranean Sea larger also that number projected fluctuate ± 10–50 during 21st century response different sequences key variability. note contributions future risks generally consistent all SMILEs. Our findings thus provide valuable information long-term disaster risk reduction management.

Language: Английский

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Performance‐based evaluation of NMME and C3S models in forecasting the June–August Central African rainfall under the influence of the South Atlantic Ocean Dipole

International Journal of Climatology, Journal Year: 2024, Volume and Issue: 44(7), P. 2462 - 2483

Published: April 16, 2024

Abstract In this study, hindcasts from eight Copernicus Climate Change Service (C3S) and three North American Multi‐Model Ensemble (NMME) operational seasonal forecast systems, based on dynamical climate models, are employed to investigate the influence of South Atlantic Ocean Dipole (SAOD) predictive skill Central Africa (CA) rainfall. The focus is primarily June–July–August season for 1993–2016. findings reveal that, when regionally averaged, all models exhibit positive in predicting CA rainfall, except Geophysical Fluid Dynamics Laboratory (GFDL‐SPEAR) model. Notably, there significant spatial variations across different regions. Model performance particularly low (high) African Republic Congo Basin (Gabon Chad) tends deteriorate with increasing lead‐time. Models that demonstrate a strong connection between SAOD rainfall tend better skills forecasting contrast weaker connections. This leads in‐phase relationship strength SAOD–rainfall among models. Furthermore, atmospheric circulation responding SST forcing associated El Niño–Southern Oscillation exerts robust climatological mean over SAO. suggests state bias SAO/equatorial Pacific region plays role modulating simulated SAOD–CA and, consequently, prediction general, both NMME C3S appear be valuable tools capable providing essential information several months advance. These insights can aid decision‐makers making informed decisions regarding adaptation mitigation measures.

Language: Английский

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Drought and flood risk mapping using a GIS-based multi-criteria decision method: A case of the Olifants Basin, South Africa

Next Sustainability, Journal Year: 2025, Volume and Issue: 6, P. 100100 - 100100

Published: Jan. 1, 2025

Language: Английский

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HERA: a high-resolution pan-European hydrological reanalysis (1951–2020)

Earth system science data, Journal Year: 2025, Volume and Issue: 17(1), P. 293 - 316

Published: Jan. 30, 2025

Abstract. Since 1950, anthropogenic activities have altered the climate, land cover, soil properties, channel morphologies, and water management in river basins of Europe. This has resulted significant changes hydrological conditions. The availability consistent estimates flow at global continental levels is a necessity for assessing cycle. To overcome limitations posed by observations (incomplete records, inhomogeneous spatial coverage), we simulate discharge Europe period 1951–2020 using state-of-the-art modelling approach. We use new European set-up OS LISFLOOD model, running 1 arcmin (≈1.8 km) with 6-hourly time steps. model forced climate reanalysis data (ERA5-Land) that are bias-corrected downscaled to resolution gridded weather observations. also incorporates 72 surface field maps representing catchment morphology, vegetation, use, demand, lakes, reservoirs. Inputs related human evolving through emulate societal changes. resulting Hydrological ReAnalysis (HERA) provides 282 521 pixels an upstream area >100 km2. assess its skill 2448 gauging stations distributed across Overall, HERA delivers satisfying results (median KGE′=0.55), despite general underestimation observed mean discharges (mean bias=-13.1 %), demonstrates capacity reproduce statistics extreme flows. performance increases size, it varies space depending on reservoir influence calibration. fine temporal enhanced compared previous based small- medium-scale catchments (100–10 000 km2). first publicly available long-term, high-resolution Despite limitations, enables analysis dynamics extremes, influences, change scale while maintaining local relevance. It creates opportunity study these ungauged dynamic socio-economic inputs via JRC catalogue: https://doi.org/10.2905/a605a675-9444-4017-8b34-d66be5b18c95 (Tilloy et al., 2024).

Language: Английский

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