Assessing climate change projections in the Volta Basin using the CORDEX-Africa climate simulations and statistical bias-correction

Yeboah, Kofi A.; Akpoti, Komlavi; Kabo-bah, Amos T.; Ofosu, Eric Antwi; Siabi, Ebenezer K.; Mortey, Eric Mensah; Okyereh, Samuel A.

doi:10.1016/j.envc.2021.100439

Cited by 34 publications

(29 citation statements)

References 56 publications

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“…Therefore, there is a high confidence in future climate warming of the VRB region in West Africa during the 21st century. These findings align with previous studies in West Africa (Dosio et al, 2020;Todzo et al, 2020;Jin et al, 2018;Yeboah et al, 2022). Similar to Dosio et al (2019), a lower RCM-GCM agreement of 63 % is found for future changes in rainfall, thereby highlighting the complexity of modelling climate in West Africa (Fitzpatrick et al, 2020;Panthou et al, 2012).…”

Section: Annual Changes In Hydroclimatic Variables and Water Availabi...supporting

confidence: 89%

Contrasting changes in hydrological processes of the Volta River basin under global warming

Dembélé

Vrac

Ceperley

et al. 2022

Hydrol. Earth Syst. Sci.

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Abstract. A comprehensive evaluation of the impacts of climate change on water resources of the West Africa Volta River basin is conducted in this study, as the region is expected to be hardest hit by global warming. A large ensemble of 12 general circulation models (GCMs) from the fifth Coupled Model Intercomparison Project (CMIP5) that are dynamically downscaled by five regional climate models (RCMs) from the Coordinated Regional-climate Downscaling Experiment (CORDEX)-Africa is used. In total, 43 RCM–GCM combinations are considered under three representative concentration pathways (RCP2.6, RCP4.5, and RCP8.5). The reliability of each of the climate datasets is first evaluated with satellite and reanalysis reference datasets. Subsequently, the Rank Resampling for Distributions and Dependences (R2D2) multivariate bias correction method is applied to the climate datasets. The bias-corrected climate projections are then used as input to the mesoscale Hydrologic Model (mHM) for hydrological projections over the 21st century (1991–2100). Results reveal contrasting dynamics in the seasonality of rainfall, depending on the selected greenhouse gas emission scenarios and the future projection periods. Although air temperature and potential evaporation increase under all RCPs, an increase in the magnitude of all hydrological variables (actual evaporation, total runoff, groundwater recharge, soil moisture, and terrestrial water storage) is only projected under RCP8.5. High- and low-flow analysis suggests an increased flood risk under RCP8.5, particularly in the Black Volta, while hydrological droughts would be recurrent under RCP2.6 and RCP4.5, particularly in the White Volta. The evolutions of streamflow indicate a future delay in the date of occurrence of low flows up to 11 d under RCP8.5, while high flows could occur 6 d earlier (RCP2.6) or 5 d later (RCP8.5), as compared to the historical period. Disparities are observed in the spatial patterns of hydroclimatic variables across climatic zones, with higher warming in the Sahelian zone. Therefore, climate change would have severe implications for future water availability with concerns for rain-fed agriculture, thereby weakening the water–energy–food security nexus and amplifying the vulnerability of the local population. The variability between climate models highlights uncertainties in the projections and indicates a need to better represent complex climate features in regional models. These findings could serve as a guideline for both the scientific community to improve climate change projections and for decision-makers to elaborate adaptation and mitigation strategies to cope with the consequences of climate change and strengthen regional socioeconomic development.

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Section: Annual Changes In Hydroclimatic Variables and Water Availabi...supporting

confidence: 89%

Contrasting changes in hydrological processes of the Volta River basin under global warming

Dembélé

Vrac

Ceperley

et al. 2022

Hydrol. Earth Syst. Sci.

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show abstract

“…Three out of the four RCMs, however, predict a prolonged rainy season with unusually higher precipitation in November. Yeboah et al (2022) also reported increased precipitation during the month of November in the Volta Basin. In northern Togo, November marks the end of the rainy season with minimal precipitation.…”

Section: Projected Changes In Climatementioning

confidence: 89%

“…Future climate trends and their potential effect on water resources in the WASS have been studied. For example, different bias-correction techniques have been used to downscale the Coupled Model Intercomparison Project (CMIP5) data for the Volta Basin in Ghana (e.g., Siabi et al 2021;Yeboah et al 2022). Overall, these studies project increasing temperatures and decreasing precipitation in the Volta Basin.…”

Section: Introductionmentioning

confidence: 99%

Assessing future climate trends and their impact on different fractured rock aquifers in Northern Togo

Akara

Reeves

Gnazou

et al. 2022

Journal of Water and Climate Change

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A fully integrated hydrologic model of the Koumfab watershed in Northern Togo is used to study the impact of climate change on water resources. Bias-corrected temperature and precipitation from four regional climate models (RCMs) and two greenhouse emissions scenarios are used as climate forcings for the integrated model. Climate projections from the four RCMs indicate a rise (1.4–5.5 °C) in average temperature from the control (1971–2000) to the future period (2031–2060). Projected precipitation follows two contrasting trends with some RCMs predicting an increase (by up to 14%) in mean annual precipitation, while others predict a decline (by up to 14%). These changes in precipitation and temperature have a noticeable effect on groundwater levels and streamflow. The model indicates a decline in groundwater levels for all future climate projections by 1.4–5.7 m. The projected streamflow at the watershed outlet shows increasing (59–332%) and decreasing trends (39–100%).

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“…Furthermore, statistical fit tests such as percentage of bias, coefficient of variation, and root mean squared error were used to evaluate the model outputs. However, when compared to observed data, the projected rainfall data contain significant biases, Climate Model for Hydrologic Modelling tool was used to downscale and bias-correct the RCMs rainfall data [ 62 , 63 ]. As a result, in scenario 3 (S3), a design storm estimated from observed and projected rainfall was inputted into the model to compare simulation results under climate change to baseline conditions [ 64 ].…”

Section: Methodsmentioning

confidence: 99%

Evaluation of climate change, urbanization, and low-impact development practices on urban flooding

Bibi

Kara

2023

Heliyon

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Assessing climate change projections in the Volta Basin using the CORDEX-Africa climate simulations and statistical bias-correction

Cited by 34 publications

References 56 publications

Contrasting changes in hydrological processes of the Volta River basin under global warming

Contrasting changes in hydrological processes of the Volta River basin under global warming

Assessing future climate trends and their impact on different fractured rock aquifers in Northern Togo

Evaluation of climate change, urbanization, and low-impact development practices on urban flooding

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