5 results on '"Dezetter, Alain"'
Search Results
2. Trend analysis of reference evapotranspiration and climate variables in the main hydrosystems of Senegal: Senegal, Gambia and Casamance River Basins.
- Author
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Ndiaye, Papa Malick, Bodian, Ansoumana, Diop, Serigne Bassirou, Diop, Lamine, Dezetter, Alain, Ogilvie, Andrew, and Djaman, Koffi
- Subjects
TREND analysis ,EVAPOTRANSPIRATION ,SOLAR radiation ,WIND speed ,WATER supply - Abstract
Analysis of reference evapotranspiration (ET 0) trends is essential for understanding the impacts of climate change on water resources. Thus, despite the continuous rise in temperatures, a decrease in evapotranspiration is noted in some parts of the world. This contrast is called the "evaporation paradox" and is thought to be related to the variation in wind speed, relative humidity and solar radiation. The objective of this work is to analyze the annual and seasonal trends of ET 0 and climate variables at the scale of the Senegal, Gambia and Casamance river basins. The reanalyze data of NASA/POWER are used over the period 1984–2019. Mann Kendall's test and Sen slope were used to analyze trends in ET 0 and climate variables. Results show that on annual scale, ET 0 increases significantly in 32 % of the Senegal basin and decreases in less than 1 % of it. In contrast, in the Casamance and Gambia basins, the annual ET 0 drops by 65 % and 18 %, respectively. On an annual scale, temperature and relative humidity show an increasing trend over all basins while wind speed and radiation decrease significantly. This confirms the existence of the "evaporation paradox" in the three basins. This phenomenon is explained by the increase in relative humidity and the decrease in wind speed and solar radiation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. ADHI: the African Database of Hydrometric Indices (1950–2018).
- Author
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Tramblay, Yves, Rouché, Nathalie, Paturel, Jean-Emmanuel, Mahé, Gil, Boyer, Jean-François, Amoussou, Ernest, Bodian, Ansoumana, Dacosta, Honoré, Dakhlaoui, Hamouda, Dezetter, Alain, Hughes, Denis, Hanich, Lahoucine, Peugeot, Christophe, Tshimanga, Raphael, and Lachassagne, Patrick
- Subjects
DATABASES ,QUALITY control ,TIME series analysis ,SCIENTIFIC community ,DATA quality ,RIVER conservation - Abstract
The African continent is probably the one with the lowest density of hydrometric stations currently measuring river discharge despite the fact that the number of operating stations was quite important until the 1970s. This new African Database of Hydrometric Indices (ADHI) provides a wide range of hydrometric indices and hydrological signatures computed from different sources of data after a quality control. It includes 1466 stations with at least 10 years of daily discharge data over the period 1950–2018. The average record length is 33 years, and 131 stations have complete records over 50 years. With this new dataset spanning most climatic regions of the African continent, several hydrometric indices have been computed, representing mean flow characteristics and extremes (low flows and floods), and are accessible to the scientific community. The database will be updated on a regular basis to include more hydrometric stations and longer time series of river discharge. The ADHI is available for download at: 10.23708/LXGXQ9 (Tramblay and Rouché, 2020). [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
4. The African Database of Hydrometric Indices (ADHI).
- Author
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Tramblay, Yves, Rouché, Nathalie, Paturel, Jean-Emmanuel, Mahé, Gil, Boyer, Jean-François, Amoussou, Ernest, Bodian, Ansoumana, Dacosta, Honoré, Dakhlaoui, Hamouda, Dezetter, Alain, Hughes, Denis, Hanich, Lahoucine, Peugeot, Christophe, Tshimanga, Raphael, and Lachassagne, Patrick
- Subjects
DATABASES ,TIME series analysis ,SCIENTIFIC community ,RIVER conservation - Abstract
The African continent is probably the one with the lowest density of hydrometric stations currently measuring river discharge, despite the fact that the number of operating stations was quite important until the 70s. This new African Database of Hydrometric Indices (ADHI) is compiling data from different sources carefully checked for quality control. It includes about 1500 stations with at least 10 years of daily discharge data over the period 1950-2018. The average record length is 19 years and for over 100 stations complete records are available over 50 years. With this dataset spanning most regions of the African continent, several hydrometric indices have been computed, representing mean flow characteristics and extremes (low flows and floods), and are made accessible to the scientific community. The database will be updated on a regular basis to include more hydrometric stations and longer time series of river discharge. The ADHI database is available for download at: https://doi.org/10.23708/LXGXQ9 (Tramblay and Rouché, 2020). [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
5. Sustainability of water uses in managed hydrosystems: human- and climate-induced changes for the mid-21st century.
- Author
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Fabre, Julie, Ruelland, Denis, Dezetter, Alain, and Grouillet, Benjamin
- Subjects
WATERSHEDS ,WATER use ,WATER management ,REGULATION of rivers ,HYDROLOGIC models ,WATER supply - Abstract
This paper assesses the sustainability of planned water uses in mesoscale river basins under multiple climate change scenarios, and contributes to determining the possible causes of unsustainability. We propose an assessment grounded in real-world water management issues, with water management scenarios built in collaboration with local water agencies. Furthermore, we present an analysis through indicators that relate to management goals and present the implications of climate uncertainty for our results, furthering the significance of our study for water management. A modeling framework integrating hydro-climatic and human dynamics and accounting for interactions between resource and demand was applied in two basins of different scales and with contrasting water uses: the Herault (2500 km², France) and the Ebro (85 000 km², Spain) basins. Natural streamflow was evaluated using a conceptual hydrological model. A demand-driven reservoir management model was designed to account for streamflow regulations from the main dams. Human water demand was estimated from time series of demographic, socioeconomic and climatic data. Environmental flows were accounted for by defining streamflow thresholds under which withdrawals were strictly limited. Finally indicators comparing water availability to demand at strategic resource and demand nodes were computed. This framework was applied under different combinations of climatic and water use scenarios for the mid-21st to differentiate the impacts of climate-and human-induced changes on streamflow and water balance. Results showed that objective monthly environmental flows would be guaranteed in current climate conditions in both basins, yet in several areas this could imply limiting human water uses more than once every 5 years. The impact of the tested climate projections on both water availability and demand could question the water allocations and environmental requirements currently planned for the coming decades. Water shortages for human use could become more frequent and intense, and the pressure on water resources and aquatic ecosystems could intensify. The causes of unsustainability vary across sub-basins and scenarios, and in most areas results are highly dependent on the climate change scenario. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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