One of the main contributions of this project are the peer-review papers to be published by the members of AMMA-2050. This space will list published outputs from the project.

 

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Klein, Cornelia; Belušić, Danijel; Taylor, Christopher M.. 2018 Wavelet scale analysis of mesoscale convective systems for detecting deep convection from infrared imagery. Journal of Geophysical Research: Atmospheres. https://doi.org/10.1002/2017JD027432Focusing on West Africa, we show that Meteosat cloud top temperatures are a useful proxy for rainfall intensities, as derived from snapshots from the Tropical Rainfall Measuring Mission 2A25 product: MCSs larger than 15,000 km2 at a temperature threshold of −40°C are found to produce 91% of all extreme rainfall occurrences in the study region, with 80% of the storms producing extreme rain when their minimum temperature drops below −80°C. We present a new method based on 2‐D continuous wavelet transform to explore the relationship between cloud top temperature and rainfall intensity for subcloud features at different length scales. 

Aymeric Ricome, François Affholder, Françoise Gérard, Bertrand Muller, Charlotte Poeydebat, Philippe Quirion, Moussa Sall. Are subsidies to weather-index insurance the best use of public funds? A bio-economic farm model applied to the Senegalese groundnut basin. Elsevier http://dx.doi.org/10.1016/j.agsy.2017.05.015

While crop yields in Sub-Saharan Africa are low compared to most other parts of the world, weather-index insurance is often presented as a promising tool, which could help resource-poor farmers in developing countries to invest and adopt yield-enhancing technologies. Here, we test this hypothesis on two contrasting areas (in terms of rainfall scarcity) of the Senegalese groundnut basin through the use of a bio-economic farm model, coupling the crop growth model CELSIUS with the economic model ANDERS, both specifically designed for this purpose. 

E.T.N’Datchoh, I.Diallo, A.Konaré, S.Silué, K.O.Ogunjobi, A,Diedhieou and M.Doumbia Dust induced changes on the West African summer monsoon feature. Royal Meteorological Society http://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.5187

Dust generation and transportation from North Africa are thought to modulate the West African Monsson (WAM) features. In this study, we investigated the relationship between the Saharan Air Layer located above Atlantic Ocean (OSAL) and WAM features, including Monsoon flow, African Easterly Jet (AEJ) and Tropical Easterly Jet (TEJ) over West Africa using the RegCM4 regional model at 30km grid resolution.

Famien, A. M., Janicot, S., Ochou, A. D., Vrac, M., Defrance, D., Sultan, B., and Noël, T.: A bias-corrected CMIP5 dataset for Africa using the CDF-t method – a contribution to agricultural impact studies, Earth Syst. Dynam., 9, 313-338, https://doi.org/10.5194/esd-9-313-2018, 2018.

This paper aims to present a new dataset of bias-corrected CMIP5 global climate model (GCM) daily data over Africa. This dataset was obtained using the cumulative distribution function transform (CDF-t) method, a method that has been applied to several regions and contexts but never to Africa… Evaluation of the results over West Africa has been carried out on a list of priority user-based metrics that were discussed and selected with stakeholders. It includes simulated yield using a crop model simulating maize growth.

Sane, Y., Panthou, G., Bodian, A., Vischel, T., Lebel, T., Dacosta, H., Quantin, G., Wilcox, C., Ndiaye, O., Diongue-Niang, A., and Diop Kane, M.: Intensity-Duration-Frequency (IDF) rainfall curves in Senegal, Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2017-352, in review, 2017.This study confirms previous works showing that simple scaling holds for characterizing the time-space structure of extreme rainfall in tropical regions such as sub-Saharan Africa. It further provides confidence intervals for the parameter estimates, and shows that the uncertainty linked to the estimation of the GEV parameters, is 3 to 4 times larger than the uncertainty linked to the inference of the scaling parameter.

Juliette Blanchet, Claire Aly, Théo Vischel, Gérémy Panthou, Youssouph Sané, Mariane Diop Kane (2018), Trend in the Co‐Occurrence of Extreme Daily Rainfall in West Africa Since 1950. 
https://doi.org/10.1002/2017JD027219

In this paper we propose a statistical framework to study the evolution of the co-occurrence of extreme daily rainfall in West Africa since 1950. Two regions are considered, subject to contrasted rainfall regimes: Senegal and the central Sahel.The paper discusses how the co-occurrence of extremes can provide a qualitative indicator on change in size and propagation of the strongest storms. 

Lafore, J.-P., Beucher, F., Peyrillé, P., Diongue-Niang, A., Chapelon, N., Bouniol, D., Caniaux, G., Favot, F., Ferry, F., Guichard, F., Poan, E., Roehrig, R. and Vischel, T. (2017), A multi-scale analysis of the extreme rain event of Ouagadougou in 2009. Q.J.R. Meteorol. Soc., 143: 3094–3109. doi:10.1002/qj.3165This study presents a multi-scale analysis of an extreme rain event that occurred in Burkina Faso on 1 September 2009 (263 mm rainfall observed at Ouagadougou). This high-impact weather system results from the combination of several favourable ingredients at different scales. This study suggests that this extreme rainfall event results from the combination of several favourable ingredients arising at different scales such as SST patterns, equatorial waves including MJO, Kelvin, ER, MRG and an AEW train, as well as a pre-existing large-scale wet spell. Further studies are necessary to confirm the relative importance of these ingredients and of their combination based on other case-studies of extreme events and on statistical studies. 

W. Zhang, M. Brandt, F. Guichard, Q. Tian, R. Fensholt (2017) Using long-term daily satellite based rainfall data (1983–2015) to analyze spatio-temporal changes in the sahelian rainfall regime Journal of Hydrology http://dx.doi.org/10.1016/j.jhydrol.2017.05.033

The sahelian rainfall regime is characterized by a strong spatial as well as intra- and inter-annual variability. Here we analyse rainfall regime variables that require daily observations: onset, cessation, and length of the wet season; seasonal rainfall amount; number of rainy days; intensity and frequency of rainfall events; number, length, and cumulative duration of dry spells.

S. Froidurot and A. Diedhiou (2017) Characteristics of wet and dry spells in the West African monsoon system Atmospheric Science Letters DOI:10.1002/asl.734 

Using 17 years (1998–2014) of daily TRMM 3B42 rainfall data, we provide a climatological characterization of wet and dry spells in West Africa, which should serve to assess the ability of climate model to simulate these high impact events. The study focuses on four sub-regions (Western and Central Sahel, Sudanian zone and Guinea Coast).

K.L. Sheen, D.M. Smith, N.J. Dunstone, R. Eade, D.P. Rowell & M. Vellinga (2017) Skilful prediction of Sahel summer rainfall on inter-annual and multi-year timescales Nature Communications DOI: 10.1038/ncomms14966

Summer rainfall in the Sahel region of Africa exhibits one of the largest signals of climatic variability and with a population reliant on agricultural productivity, the Sahel is particularly vulnerable to major droughts such as occurred in the 1970s and 1980s. Rainfall levels have subsequently recovered, but future projections remain uncertain. Here we show that Sahel rainfall is skilfully predicted on inter-annual and multi-year (that is, 5 years) timescales and use these predictions to better understand the driving mechanisms.

C.M. Taylor, D. Belušić, FGuichard, D. J. Parker, T. Vischel, O. Bock, P.P. Harris, S. Janicot, C. Klein & Gérémy Panthou (2017) Frequency of extreme Sahelian storms tripled since 1982 in satellite observations Nature 544, 475–478 doi:10.1038/nature22069

This study reveals global warming is responsible for a tripling in the frequency of extreme West African Sahel storms observed in just the last 35 years. The study, which has analysed trends from 35 years of satellite observations across Africa, provides unique insight into how some of the most violent storms in the world are responding to rising global temperatures. The research indicates that MCS intensification is linked to increasingly hot conditions in the Sahara desert resulting from man-made greenhouse gas emissions. 

A. J. Hartley, D.J. Parker, L. Garcia-Carreras, S. Webster (2016) Simulation of vegetation feedbacks on local and regional scale precipitation in West Africa Agricultural and Forest Meteorology http://dx.doi.org/10.1016/j.agrformet.2016.03.001

Planned changes to land use in West Africa have been proposed to both combat desertification and to preserve biodiversity in the region, however, there is an urgent need for tools to assess the effects of these proposed changes on local and regional scale precipitation. We use a high-resolution, convection-permitting numerical weather prediction (NWP) model to study how the initiation and propagation of mesoscale convective systems (MCS) depends on the surface vegetation cover.

B. Sultan and M. Gaetani (2016): Agriculture in West Africa in the Twenty-first Century: climate change and impacts scenarios, and potential for adaptation, Crop Science and Horticulture, http://dx.doi.org/10.3389/fpls.2016.01262

This review paper provides a comprehensive overview of climate change impacts on agriculture in West Africa based on the recent scientific literature.

P. Good, B. B.B. Booth, R.  Chadwick, E. Hawkins, A. Jonko & J. A. Lowe (2016) Large differences in regional precipitation change between a first and second 2 K of global warming Nature Communications DOI: 10.1038/ncomms13667

For adaptation and mitigation planning, stakeholders need reliable information about regional precipitation changes under different emissions scenarios and for different time periods. A significant amount of current planning effort assumes that each K of global warming produces roughly the same regional climate change. Here using 25 climate models, we compare precipitation responses with three 2 K intervals of global ensemble mean warming.

K. Guan, B. Sultan, M. Biasutti, C. Baron, D.B. Lobell (2016): Assessing climate adaptation options and uncertainties for cereal systems in West Africa, Agricultural and Forest Meteorology, http://dx.doi.org/10.1016/j.agrformet.2016.07.021

In the coming decades, the fragile agricultural system in West Africa will face further challenges in meeting food security, both from increasing population and climate change. Optimal prioritization of adaptation investments requires the assessment of possible adaptation options and their uncertainties. We adopt a new assessment framework to account for the impacts of proposed adaptation options in the historical climate and their ability to reduce the impacts of future climate change.

A. J. Challinor, A.-K. Koehler, J. Ramirez-Villegas, S. Whitfield  and B. Das (2016): Current warming will reduce yields unless maize breeding and seed systems adapt immediately, Nature Climate Change, doi:10.1038/nclimate3061

Crop yields will fall within the next decade due to climate change unless immediate action is taken to speed up the introduction of new and improved varieties, experts have warned. The research, led by the University of Leeds and published in the journal Nature Climate Change, focusses on maize in Africa but the underlying processes affect crops across the tropics. The CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) funded the study. This research was partly funded by the NERC/DFID Future Climate For Africa programme.