Future changes in precipitation, evapotranspiration and streamflows in the Mono Basin of West Africa

Abstract. The impact of climate change on precipitation and water availability is of major concern for policy makers in the Mono Basin of West Africa, whose economy mainly depends on rainfed agriculture and hydropower generation. The objective of this study is to project rainfall, flows and evapotranspiration (ET) in the future period and understand their changes across Mono River Basin. Observed data were considered for the historical period 1980–2010, and a Multi-model ensemble for future projections data of eight selected Regional Climate Models under RCP 4.5 and RCP 8.5 over the periods 2011–2100 was used. The GR4J model was used to simulate daily flows of the Mono watershed. The ensemble mean shows a decrease and increase streamflows between −54 % and 42 %, −58 % and 31 % under the RCP4.5, RCP8.5 scenario, respectively. The greatest decreases of high flows is projected to occur in the near term under RCP8.5, whereas the greatest decrease of low flows is projected to occur in the long term under the same RCP. For the rainfall and ET, the both scenarios (RCP4.5 and RCP8.5) predict an increase of ET while the rainfall will decrease. The results of this study of would be very useful in the choice of management and adaptation policies for water resources management.

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Assessment of climate change impact on hydrology of a transboundary river of Bhutan and India

Journal of Water and Climate Change ◽

10.2166/wcc.2021.338 ◽

2021 ◽

Author(s):

Phub Zam ◽

Sangam Shrestha ◽

Aakanchya Budhathoki

Keyword(s):

Climate Change ◽

Climate Models ◽

Assessment Tool ◽

Regional Climate ◽

Flow Simulation ◽

Water Security ◽

Regional Climate Models ◽

Transboundary River ◽

Rcp 8.5 ◽

The Impact

Abstract Assessing the impacts of climate change on a transboundary river plays an important role in sustaining water security within as well as beyond the national boundaries. At times, the unilateral decision taken by one country can increase the risk of negative effect on the riparian countries and if the impact is felt strongly by the other country, it can lead to international tension between them. This study examines the impact of climate change on hydrology between a shared river which is Wangchu river in Bhutan and Raidak river in India. The river is mainly used to produce hydropower in the two largest hydropower plants on which the majority of Bhutan's economic development depends and is mainly used for agriculture in India. The Soil and Water Assessment Tool (SWAT) was used for future flow simulation. Future climate was projected for near future (NF) from 2025–2050 and far future (FF) from 2074–2099 using an ensemble of three regional climate models (ACCESS, CNRM-CM5 and MPI-ESM-LR) for two RCPs (Representative Concentration Pathways), RCP 4.5 and RCP 8.5 scenario. The ensemble results indicated that, in future, the study area would become warmer with temperature increase of 1.5 °C under RCP 4.5 and 3.6 °C under RCP 8.5. However, as per RCP 4.5 and RCP 8.5, rainfall over the study area is projected to decrease by 1.90% and 1.38% respectively. As a consequence of the projected decrease in rainfall, the flow in river is projected to decrease by 5.77% under RCP 4.5 and 4.73% under RCP 8.5. Overall, the results indicated that the degree of hydrological change is expected to be higher, particularly for low flows in both Wangchu and Raidak River. Since transboundary water is a shared for economic growth, climate change adaptation and opportunities should also be considered by both the nations for better water management.

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Wind Power Potential in Near Future Climate Scenarios: The Case for Burundi (East Africa)

Asian Journal of Environment & Ecology ◽

10.9734/ajee/2018/v8i430080 ◽

2019 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Agnidé Emmanuel Lawin ◽

Manirakiza Célestin ◽

Lamboni Batablinlé

Keyword(s):

Wind Power ◽

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Future Climate ◽

Historical Period ◽

Climate Scenarios ◽

Local Climate ◽

Rcp 8.5 ◽

Near Future

This paper assessed projected changes of wind power potential in near future climate scenarios over four sites from two contrasting regions of Burundi. Observed and MERRA-2 data sets were considered for the historical period 1981-2010, and a computed Multi-model ensemble for future projections data of eight Regional Climate Models under RCP 4.5 and 8.5 over the period 2011-2040 was used. Regional Climate Models were downscaled at local climate using Empirical Statistical Downscaling method. Mann-Kendall’s test was used for trend analysis over the historical period, while future changes in wind power density (WPD) quartiles were computed for each climate scenario by 2040. The findings revealed an increase in wind power potential all over the area studied with higher values during summer time. Indeed, over the period 2011-2040, the lowest WPD change is projected at Northern highlands (NHL) under RCP 4.5 with 27.03 W.m-2, while the highest WPD change of 46.34 W.m-2 is forecasted under RCP 8.5 at Southern Imbo plain (SIP). The month of August and September are expected to have higher WPD change in RCP 4.5 and RCP 8.5, respectively while January is projected to have the lowest WPD. Places near by the Lake Tanganyika are the most favorable areas for wind power generation.

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Evaluation of uncertainties in mean and extreme precipitation under climate change for northwestern Mediterranean watersheds from high-resolution Med and Euro-CORDEX ensembles

Hydrology and Earth System Sciences ◽

10.5194/hess-22-673-2018 ◽

2018 ◽

Vol 22 (1) ◽

pp. 673-687 ◽

Cited By ~ 10

Author(s):

Antoine Colmet-Daage ◽

Emilia Sanchez-Gomez ◽

Sophie Ricci ◽

Cécile Llovel ◽

Valérie Borrell Estupina ◽

...

Keyword(s):

Climate Change ◽

High Resolution ◽

Extreme Precipitation ◽

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Historical Period ◽

Mountainous Regions ◽

Extreme Precipitation Events ◽

Precipitation Events

Abstract. The climate change impact on mean and extreme precipitation events in the northern Mediterranean region is assessed using high-resolution EuroCORDEX and MedCORDEX simulations. The focus is made on three regions, Lez and Aude located in France, and Muga located in northeastern Spain, and eight pairs of global and regional climate models are analyzed with respect to the SAFRAN product. First the model skills are evaluated in terms of bias for the precipitation annual cycle over historical period. Then future changes in extreme precipitation, under two emission scenarios, are estimated through the computation of past/future change coefficients of quantile-ranked model precipitation outputs. Over the 1981–2010 period, the cumulative precipitation is overestimated for most models over the mountainous regions and underestimated over the coastal regions in autumn and higher-order quantile. The ensemble mean and the spread for future period remain unchanged under RCP4.5 scenario and decrease under RCP8.5 scenario. Extreme precipitation events are intensified over the three catchments with a smaller ensemble spread under RCP8.5 revealing more evident changes, especially in the later part of the 21st century.

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A tale of two futures: contrasting scenarios of future precipitation for West Africa from an ensemble of regional climate models

Environmental Research Letters ◽

10.1088/1748-9326/ab7fde ◽

2020 ◽

Vol 15 (6) ◽

pp. 064007 ◽

Cited By ~ 5

Author(s):

Alessandro Dosio ◽

Andrew G Turner ◽

Alain T Tamoffo ◽

Mouhamadou Bamba Sylla ◽

Christopher Lennard ◽

...

Keyword(s):

West Africa ◽

Climate Models ◽

Regional Climate ◽

Regional Climate Models

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Evaluating the effect of climate change on snow load on structures

IABSE Symposium, Guimarães 2019: Towards a Resilient Built Environment Risk and Asset Management ◽

10.2749/guimaraes.2019.0666 ◽

2019 ◽

Cited By ~ 1

Author(s):

Pietro Croce ◽

Paolo Formichi ◽

Filippo Landi ◽

Francesca Marsili

Keyword(s):

Climate Change ◽

Climate Models ◽

Regional Climate ◽

Climate Extremes ◽

Regional Climate Models ◽

Extreme Weather Events ◽

Uncertainty Range ◽

Greenhouse Gasses ◽

Weather Events ◽

The Impact

As consequence of global warming extreme weather events might become more frequent and severe across the globe. The evaluation of the impact of climate change on extremes is then a crucial issue for the resilience of infrastructures and buildings and is a key challenge for adaptation planning. In this paper, a suitable procedure for the estimation of future trends of climatic actions is presented starting from the output of regional climate models and taking into account the uncertainty in the model itself. In particular, the influence of climate change on ground snow loads is discussed in detail and the typical uncertainty range is determined applying an innovative algorithm for weather generation. Considering different greenhouse gasses emission scenarios, some results are presented for the Italian Mediterranean region proving the ability of the method to define factors of change for climate extremes also allowing a sound estimate of the uncertainty range associated with different models.

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The Mesoscale Response to Global Warming over the Pacific Northwest Evaluated Using a Regional Climate Model Ensemble

Journal of Climate ◽

10.1175/jcli-d-21-0061.1 ◽

2021 ◽

pp. 1-56

Keyword(s):

Global Warming ◽

Pacific Northwest ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Wrf Model ◽

Regional Climate Models ◽

Winter Precipitation ◽

Historical Period ◽

Continental Interior

This paper describes the downscaling of an ensemble of twelve GCMs using the WRF model at 12-km grid spacing over the period 1970-2099, examining the mesoscale impacts of global warming as well as the uncertainties in its mesoscale expression. The RCP 8.5 emissions scenario was used to drive both global and regional climate models. The regional climate modeling system reduced bias and improved realism for a historical period, in contrast to substantial errors for the GCM simulations driven by lack of resolution. The regional climate ensemble indicated several mesoscale responses to global warming that were not apparent in the global model simulations, such as enhanced continental interior warming during both winter and summer as well as increasing winter precipitation trends over the windward slopes of regional terrain, with declining trends to the lee of major barriers. During summer there is general drying, except to the east of the Cascades. April 1 snowpack declines are large over the lower to middle slopes of regional terrain, with small snowpack increases over the lower elevations of the interior. Snow-albedo feedbacks are very different between GCM and RCM projections, with the GCM’s producing large, unphysical areas of snowpack loss and enhanced warming. Daily average winds change little under global warming, but maximum easterly winds decline modestly, driven by a preferential sea level pressure decline over the continental interior. Although temperatures warm continuously over the domain after approximately 2010, with slight acceleration over time, occurrences of temperature extremes increase rapidly during the second half of the 21st century.

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Changes in extreme surface solar radiation in EURO-CORDEX Regional Climate Models

10.5194/egusphere-egu21-16536 ◽

2021 ◽

Author(s):

Blanka Bartok

Keyword(s):

Climate Change ◽

Power Generation ◽

Solar Radiation ◽

Solar Energy ◽

Electricity Generation ◽

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Surface Solar Radiation ◽

The Impact

As solar energy share is showing a significant growth in the European electricity generation system, assessments regarding long-term variation of this variable related to climate change are becoming more and more relevant for this sector. Several studies analysed the impact of climate change on the solar energy sector in Europe (Jerez et al, 2015) finding light impact (-14%; +2%) in terms of mean surface solar radiation. The present study focuses on extreme values, namely on the distribution of low surface solar radiation (overcast situation) and high surface solar radiation (clear sky situation), since the frequencies of these situations have high impact on electricity generation.The study considers 11 high-resolution (0.11 deg) bias-corrected climate projections from the EURO-CORDEX ensemble with 5 Global Climate Models (GCMs) downscaled by 6 Regional Climate Models (RCMs).Changes in extreme surface solar radiation frequencies show different regional patterns over Europe.The study also includes a case study determining the changes in solar power generation induced by the extreme situations.&#160;&#160;Jerez et al (2015): The impact of climate change on photovoltaic power generation in Europe, Nature Communications 6(1):10014, 10.1038/ncomms10014&#160;

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Impact of aerosols on the future Euro-Mediterranean climate: results from the CORDEX FPS-Aerosol

10.5194/egusphere-egu21-2211 ◽

2021 ◽

Author(s):

Pierre Nabat ◽

Samuel Somot ◽

Lola Corre ◽

Eleni Katragkou ◽

Shuping Li ◽

...

Keyword(s):

Mediterranean Climate ◽

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Surface Radiation ◽

Climate Change Signal ◽

Historical Period ◽

Future Evolution ◽

Aerosol Forcing ◽

The Future

The Euro-Mediterranean region is subject to numerous and various aerosol loads, which interact with radiation, clouds and atmospheric dynamics, with ensuing impact on regional climate. However up to now, aerosol variations are hardly taken into account in most regional climate simulations, although anthropogenic emissions have been dramatically reduced in Europe since the 1980s. Moreover, inconsistencies between regional climate models (RCMs) and their driving global model (GCM) have recently been identified in terms of future radiation and temperature evolution, which could be related to the differences in aerosol forcing.&#160; The present study aims at assessing the role of aerosols in the future evolution of the Euro-Mediterranean climate, using a specific multi-model protocol carried out in the Flagship Pilot Study "Aerosol" of the CORDEX program. This protocol relies on three simulations for each RCM: a historical run (1971-2000) and two future RCP8.5 simulations (2021-2050), a first one with evolving aerosols, and a second one with the same aerosols as in the historical period. Six modeling groups have taken part in this protocol, providing nine triplets of simulations. The analysis of these simulations will be presented here. First results show that the future evolution of aerosols has a significant impact on the evolution of surface radiation and surface temperature. In addition RCM runs taking into account the evolution of aerosols are simulating climate change signal closer to the one of their driving GCM than those with constant aerosols.

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Intraseasonal Precipitation Variability over West Africa under 1.5 °C and 2.0 °C Global Warming Scenarios: Results from CORDEX RCMs

Climate ◽

10.3390/cli8120143 ◽

2020 ◽

Vol 8 (12) ◽

pp. 143

Author(s):

Obed M. Ogega ◽

Benjamin A. Gyampoh ◽

Malcolm N. Mistry

Keyword(s):

Global Warming ◽

West Africa ◽

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Future Change ◽

North West ◽

Intensity Index ◽

South West Africa ◽

Projected Changes

This study assessed the performance of 24 simulations, from five regional climate models (RCMs) participating in the Coordinated Regional Climate Downscaling Experiment (CORDEX), in representing spatiotemporal characteristics of precipitation over West Africa, compared to observations. The top five performing RCM simulations were used to assess future precipitation changes over West Africa, under 1.5 °C and 2.0 °C global warming levels (GWLs), following the representative concentration pathway (RCP) 8.5. The performance evaluation and future change assessment were done using a set of seven ‘descriptors’ of West African precipitation namely the simple precipitation intensity index (SDII), the consecutive wet days (CWD), the number of wet days index (R1MM), the number of wet days with moderate and heavy intensity precipitation (R10MM and R30MM, respectively), and annual and June to September daily mean precipitation (ANN and JJAS, respectively). The performance assessment and future change outlook were done for the CORDEX–Africa subdomains of north West Africa (WA-N), south West Africa (WA-S), and a combination of the two subdomains. While the performance of RCM runs was descriptor- and subregion- specific, five model runs emerged as top performers in representing precipitation characteristics over both WA-N and WA-S. The five model runs are CCLM4 forced by ICHEC-EC-EARTH (r12i1p1), RCA4 forced by CCCma-CanESM2 (r1i1p1), RACMO22T forced by MOHC-HadGEM2-ES (r1i1p1), and the ensemble means of simulations made by CCLM4 and RACMO22T. All precipitation descriptors recorded a reduction under the two warming levels, except the SDII which recorded an increase. Unlike the WA-N that showed less frequency and more intense precipitation, the WA-S showed increased frequency and intensity. Given the potential impact that these projected changes may have on West Africa’s socioeconomic activities, adjustments in investment may be required to take advantage of (and enhance system resilience against damage that may result from) the potential changes in precipitation.

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The impact of RCM formulation and resolution on simulated precipitation in Africa

10.5194/esd-2019-55 ◽

2019 ◽

Cited By ~ 2

Author(s):

Minchao Wu ◽

Grigory Nikulin ◽

Erik Kjellström ◽

Danijel Belušić ◽

Colin Jones ◽

...

Keyword(s):

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Horizontal Resolution ◽

Added Value ◽

Primary Control ◽

Model Formulation ◽

Simulated Precipitation ◽

Mean Climate ◽

The Impact

Abstract. We investigate the impact of model formulation and horizontal resolution on the ability of Regional Climate Models (RCMs) to simulate precipitation in Africa. Two RCMs – SMHI-RCA4 and HCLIM38-ALADIN are utilized for downscaling the ERA-Interim reanalysis over Africa at four different resolutions: 25, 50, 100 and 200 km. Additionally to the two RCMs, two different configurations of the same RCA4 are used. Contrasting different RCMs, configurations and resolutions it is found that model formulation has the primary control over many aspects of the precipitation climatology in Africa. Patterns of spatial biases in seasonal mean precipitation are mostly defined by model formulation while the magnitude of the biases is controlled by resolution. In a similar way, the phase of the diurnal cycle is completely controlled by model formulation (convection scheme) while its amplitude is a function of resolution. Although higher resolution in many cases leads to smaller biases in the time mean climate, the impact of higher resolution is mixed. An improvement in one region/season (e.g. reduction of dry biases) often corresponds to a deterioration in another region/season (e.g. amplification of wet biases). The experiments confirm a pronounced and well known impact of higher resolution – a more realistic distribution of daily precipitation. Even if the time-mean climate is not always greatly sensitive to resolution, what the time-mean climate is made up of, higher order statistics, is sensitive. Therefore, the realism of the simulated precipitation increases as resolution increases. Our results show that improvements in the ability of RCMs to simulate precipitation in Africa compared to their driving reanalysis in many cases are simply related to model formulation and not necessarily to higher resolution. Such model formulation related improvements are strongly model dependent and in general cannot be considered as an added value of downscaling.

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