AMMA-2050 NEC05274
Lead Research Organisation:
Met Office
Department Name: Climate Science
Abstract
Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
Planned Impact
The primary impacts of AMMA-2050 will be: the enhanced uptake of the products of climate science in medium term decision-making in West Africa; and the growth of regional expertise in climate science, its impacts and the science-decision making interface.
The AMMA-2050 project combines novel scientific excellence along with fully integrated participation of stakeholders. We are building on the community of researchers and operational partners established in AMMA since 2003, which already has a strong track record of collaborative, multidisciplinary and impact-focused science. Within AMMA-2050 we aim to use this community to derive practical impact from our research, and to demonstrate specific applications of robust climate projections to planning in the agricultural and urban flood-risk sectors.
In order to deliver impact in the use of reliable climate information in these sectors, it is necessary to address the fundamental weaknesses in current climate science and the information it delivers. This physical science research in Pillar 1 of the project will be conducted in very close cooperation with a programme of applied research (Pillar 2) and practical demonstration projects (Pillar 3). Sustained communication among these groups is essential to the delivery of practical outputs that are relevant to users. For example, key measures of high-impact climatic quantities (drought, flooding etc) will be defined within the whole consortium and coordinated at the top level, so that such measures are both useful to users within the demonstration projects, and scientifically rigorous in the climate models. Furthermore, the credibility of climate information relies on the transparent evaluation of the information in terms of its accuracy and reliability. The legitimacy of the climate information will be ensured by the co-production of knowledge by institutions in Africa and Europe and by stakeholders and scientists working together on the project. Since excellent science is a major driver of the work of AMMA-2050, we aim to publish our results in the top peer-reviewed journals, and present the research at national and international meetings.
Existing partnerships and networks are the foundation upon which our communications are built. Within AMMA-2050, stakeholders have a defined role in ensuring the work is demand-led. Our knowledge exchange activities will draw on the networks our partners have in West Africa as well as involving boundary organisations such as the CCKE-Unit. Ongoing engagement of these organisations will ensure outputs of AMMA-2050 are communicated beyond our original list of stakeholders to a wider audience of interest groups. In this, we will work with regional and international agencies such as the Volta Basin Authority (VBA), the Climate Change, Agriculture and Food Security (CCAFS) programme, the African Centre of Meteorological Application for Development (ACMAD), the Economic Community Of West African States (ECOWAS), and government departments such as the Direction de la Gestion et de la Planification des Ressources en Eau (DGPRE) in Dakar.
The capacity building activities of AMMA-2050 will involve a balance of staff time visiting African and European research centres and policy placements totalling more than 60 months. Alongside attendance at international conferences and annual consortium meetings, plus significant leadership roles, the project will help to develop a skilled workforce and a new generation of leaders in African research. The ultimate beneficiaries of AMMA-2050 will be the populations of West Africa, who will benefit from more effective use of climate information in planning for an uncertain future. This is particularly so in the key areas of food security, via informed adaptive cropping and agricultural policies, and cities which are resilient to future flood risk.
The AMMA-2050 project combines novel scientific excellence along with fully integrated participation of stakeholders. We are building on the community of researchers and operational partners established in AMMA since 2003, which already has a strong track record of collaborative, multidisciplinary and impact-focused science. Within AMMA-2050 we aim to use this community to derive practical impact from our research, and to demonstrate specific applications of robust climate projections to planning in the agricultural and urban flood-risk sectors.
In order to deliver impact in the use of reliable climate information in these sectors, it is necessary to address the fundamental weaknesses in current climate science and the information it delivers. This physical science research in Pillar 1 of the project will be conducted in very close cooperation with a programme of applied research (Pillar 2) and practical demonstration projects (Pillar 3). Sustained communication among these groups is essential to the delivery of practical outputs that are relevant to users. For example, key measures of high-impact climatic quantities (drought, flooding etc) will be defined within the whole consortium and coordinated at the top level, so that such measures are both useful to users within the demonstration projects, and scientifically rigorous in the climate models. Furthermore, the credibility of climate information relies on the transparent evaluation of the information in terms of its accuracy and reliability. The legitimacy of the climate information will be ensured by the co-production of knowledge by institutions in Africa and Europe and by stakeholders and scientists working together on the project. Since excellent science is a major driver of the work of AMMA-2050, we aim to publish our results in the top peer-reviewed journals, and present the research at national and international meetings.
Existing partnerships and networks are the foundation upon which our communications are built. Within AMMA-2050, stakeholders have a defined role in ensuring the work is demand-led. Our knowledge exchange activities will draw on the networks our partners have in West Africa as well as involving boundary organisations such as the CCKE-Unit. Ongoing engagement of these organisations will ensure outputs of AMMA-2050 are communicated beyond our original list of stakeholders to a wider audience of interest groups. In this, we will work with regional and international agencies such as the Volta Basin Authority (VBA), the Climate Change, Agriculture and Food Security (CCAFS) programme, the African Centre of Meteorological Application for Development (ACMAD), the Economic Community Of West African States (ECOWAS), and government departments such as the Direction de la Gestion et de la Planification des Ressources en Eau (DGPRE) in Dakar.
The capacity building activities of AMMA-2050 will involve a balance of staff time visiting African and European research centres and policy placements totalling more than 60 months. Alongside attendance at international conferences and annual consortium meetings, plus significant leadership roles, the project will help to develop a skilled workforce and a new generation of leaders in African research. The ultimate beneficiaries of AMMA-2050 will be the populations of West Africa, who will benefit from more effective use of climate information in planning for an uncertain future. This is particularly so in the key areas of food security, via informed adaptive cropping and agricultural policies, and cities which are resilient to future flood risk.
Organisations
Publications
Berthou S
(2019)
Improved climatological precipitation characteristics over West Africa at convection-permitting scales
in Climate Dynamics
Berthou S
(2019)
Larger Future Intensification of Rainfall in the West African Sahel in a Convection-Permitting Model
in Geophysical Research Letters
Bickle M
(2021)
Understanding mechanisms for trends in Sahelian squall lines: Roles of thermodynamics and shear
in Quarterly Journal of the Royal Meteorological Society
Colman, A.
(2017)
Meteorology of Tropical West Africa: The Forecasters' Handbook
Diedhiou A
(2018)
Changes in climate extremes over West and Central Africa at 1.5 °C and 2 °C global warming
in Environmental Research Letters
Fitzpatrick R
(2020)
What Drives the Intensification of Mesoscale Convective Systems over the West African Sahel under Climate Change?
in Journal of Climate
Good P
(2016)
Large differences in regional precipitation change between a first and second 2 K of global warming.
in Nature communications
Hartley A
(2016)
Simulation of vegetation feedbacks on local and regional scale precipitation in West Africa
in Agricultural and Forest Meteorology
| Description | WP1.3: Analysis of daily precipitation: total precipitation, number of wet days, precipitation distribution, amount-duration-frequency histograms compared with TRMM, GPCC and CHIRPS. The dry bias of the global model on West Africa is much reduced in CP4 through a better representation of the whole daily precipitation distribution. CP4 is very close to TRMM distribution (much closer than the 25km resolution control) except over orography and over the ocean where precipitation is too intense in the model. The zonal propagation of convection in CP4 is close to TRMM too. WP2.1: Co-led strategic planning for a capacity-building Metrics Training Workshop Contributing to implementation of Metrics Training Workshop Contributed to FCFA Modular Report WP2.2: Assessing which user-relevant climate metrics can be clustered together to use the same set of CMIP5 model-weights (utilising HyCRISTAL methodology & software). Decomposition of CMIP5 change and spread in rainfall change, following Chadwick methodology. Assessing links with potential drivers of uncertainty in CMIP5 rainfall change. March 2018: WP1.3: Further evaluation of CP4A v R25A representation of user-relevant metrics of climate extremes WP2.1: - Work has started on evaluating the potential for future aerosol reductions from industrialised nations in impacting West African Sahel rainfall. Idealised simulations (using HadGEM3) provide information on the rainfall signal arising from reductions in different regions (e.g. N. America, Europe, East Asia). We've looked to assess the degree of robustness in these signals across current modelling uncertainty by comparing these changes to other experiments in the PDRMIP dataset - and the early outlook is encouraging with indications of model agreement, in the large scales. - Led the production of two draft atlases of the changes and uncertainties in user-relevant climate metrics, contributed substantial coding, and led the review process. The full version 1 series of atlases is now about to be released. - Led the start of discussions on the best approach to integrate P1 work to provide expert judgement of future HIW was initiated at Nov 2016 AGM, and will continue at Nov 2017 WP2 Virtual and Feb 2018 AGM. WP2.2: - More detailed analysis of the characteristics of change in each ensemble member has been conducted. This allows us to learn more about the change occurring and identify potential drivers of change. Work has been done to understand how and why outliers behave differently in terms of the large scale drivers of precipitation change, and progress towards identifying what the mechanisms of change are that relate to the characteristics of change. - Model weights have been derived for 39 CMIP5 models to help refine seasonal uncertainty in future temperature change. Weights account for sources of uncertainty in global warming that are not well characterised by the CMIP5 ensemble (e.g. carbon cycle feedbacks) and observational constraints on global warming, leading to refined PDFs of regional warming estimates. - Work on assessing the seasonal uncertainty in the temperature gradient is currently focused on assessing the influence of warming vs direct CO2 on inter-model diversity using the amip4K and amip4xCO2 CMIP5 ensembles. WP2.3: Begun to analyse CP4A v R25A projections of future changes in user-relevant metrics of climate extremes Future temperature increases in West Africa will have a detrimental effect on the communities living there (e.g. on health and possibly reduced crop yields). To support assessments of climate change impacts, we propose a method for refining regional temperature projections and demonstrate its application to West Africa. A focus is on characterising uncertainty more comprehensively. We find a strong, but spatially varying, inter-model correlation between regional warming in West Africa over the 21st century and global mean warming in the Coupled Model Intercomparison Project phase 5 (CMIP5) simulations. Noting this, we calculate a transformation between a frequency distribution of CMIP5-simulated global warming values and a broader published probability distribution of global warming. The latter draws on a perturbed parameter ensemble of model simulations to account for uncertainties related to the atmosphere, ocean, carbon cycle and aerosol processes that are not well characterised by the CMIP5 ensemble. We apply the transformation to CMIP5-derived distributions for warming in different regions of West Africa to obtain regional warming distributions with longer tails than distributions estimated directly from the CMIP5 ensemble. Our results imply that CMIP5-based assessments of temperature-sensitive applications may underestimate the probability of large (and small) impacts. In some cases, the transformation that we develop for regional warming could also be applied to distributions of temperature-driven climate change impacts to ensure that they better reflect known uncertainties in future climate change. The West African climate is unique and challenging to reproduce using standard resolution climate models as a large proportion of precipitation comes from organised deep convection. For the first time, a regional 4.5 km convection permitting simulation was performed on a pan-African domain for a period of 10 years (1997-2006). The 4.5 km simulation (CP4A) is compared with a 25x40 km convection-parameterised model (R25) over West Africa. CP4A shows increased mean precipitation, which results in improvements in the mature phase of the West African monsoon but deterioration in the early and late phases. The distribution of precipitation rates is improved due to more short lasting intense rainfall events linked with mesoscale convective systems. Consequently, the CP4A model shows a better representation of wet and dry spells. The diurnal cycle of rainfall is improved, which impacts the diurnal cycle of monsoon winds and increases moisture convergence in the Sahel. Although shortcomings were identified, with implications for model development, this convection-permitting model provides a much more reliable precipitation distribution than its convection-parameterised counterpart at both daily and sub-daily time-scales. Convection-permitting scales will therefore be useful to address the crucial question of how the precipitation distribution will change in the future. Projected changes in the intensity of severe rain events over the North African Sahel-falling from large mesoscale convective systems-cannot be directly assessed from global climate models due to their inadequate resolution and parameterization of convection. Instead, the large-scale atmospheric drivers of these storms must be analyzed. Here we study changes in meridional lower-tropospheric temperature gradient across the Sahel (DTGrad), which affect storm development via zonal vertical wind shear and Saharan air layer characteristics. Projected changes in DTGrad vary substantially among models, adversely affecting planning decisions that need to be resilient to adverse risks, such as increased flooding. This study seeks to understand the causes of these projection uncertainties and finds three key drivers. The first is intermodel variability in remote warming, which has strongest impact on the eastern Sahel, decaying toward the west. Second, and most important, a warming-advection-circulation feedback in a narrow band along the southern Sahara varies in strength between models. Third, variations in southern Saharan evaporative anomalies weakly affect DTGrad, although for an outlier model these are sufficiently substantive to reduce warming here to below that of the global mean. Together these uncertain mechanisms lead to uncertain southern Saharan/northern Sahelian warming, causing the bulk of large intermodel variations in DTGrad. In the southern Sahel, a local negative feedback limits the contribution to uncertainties in DTGrad. This new knowledge of DTGrad projection uncertainties provides understanding that can be used, in combination with further research, to constrain projections of severe Sahelian storm activity. |
| Exploitation Route | Ultimately this work is intended to enable better informed long-term decision making for climate resilience |
| Sectors | Agriculture, Food and Drink,Environment |