S. A?-it-mesbah, J. L. Dufresne, F. Cheruy, and F. Hourdin, The role of thermal inertia in the representation of mean and diurnal range of surface temperature in semiarid and arid regions, GCM facing West Africa in-situ data, vol.42, pp.7572-7580, 2015.

S. M. Bateni, D. Entekhabi, S. Margulis, F. Castelli, and L. Kergoat, Coupled estimation of surface heat fluxes and vegetation dynamics from remotely sensed land surface temperature and fraction of photosynthetically active radiation, Water Resources Research, vol.50, pp.8420-8440, 2014.

A. K. Betts, Understanding hydrometeorology using global models, Bulletin of American Meteorological Society, vol.85, pp.1673-1688, 2004.

A. K. Blackadar, The vertical distribution of wind and turbulent exchange in neutral atmosphere, Journal of Geophysical Research, vol.67, pp.3095-3102, 1962.

S. Bony and K. A. Emanuel, A parameterization of the cloudiness associated with cumulus convection; evaluation using TOGA COARE data, Journal of Atmospheric Sciences, vol.58, pp.3158-3183, 2001.

F. C. Bosveld, P. Baas, G. Steeneveld, A. A. Holtslag, W. M. Angevine et al., The Third GABLS intercomparison case for evaluation studies of boundary-layer models. Part B: Results and process understanding, Boundary-Layer Meteorology, vol.152, pp.157-187, 2014.

N. Boulain, B. Cappelaere, D. Ramier, H. B. Issoufou, O. Halilou et al.,

F. Timouk, Towards an understanding of coupled physical and biological processes in the cultivated Sahel -2. Vegetation and carbon dynamics, Journal of Hydrology, vol.375, pp.190-203, 2009.
URL : https://hal.archives-ouvertes.fr/bioemco-00392769

D. Bouniol, F. Couvreux, P. Kamsu-tamo, M. Leplay, F. Guichard et al., Diurnal and seasonal cycles of cloud occurrences, types, and radiative impact over West Africa, Journal of Applied Meteorology and Climatology, vol.51, pp.534-553, 2012.

A. Cescatti, B. Marcolla, S. K. Vannan, J. Y. Pan, M. O. Rom-an et al., Intercomparison of MODIS albedo retrievals and in situ measurements across the global FLUXNET network, Remote Sensing of Environment, vol.121, pp.323-334, 2012.

J. G. Charney, Dynamics of deserts and drought in the Sahel, Quarterly Journal of the Royal Meteorological Society, vol.101, pp.193-202, 1975.

F. Cheruy, A. Campoy, J. Dupont, A. Ducharne, F. Hourdin et al.,

A. Idelkadi, Combined influence of atmospheric physics and soil hydrology on the simulated meteorology at the SIRTA atmospheric observatory, Climate Dynamics, vol.40, pp.2251-2269, 2013.
URL : https://hal.archives-ouvertes.fr/hal-00724478

O. Coindreau, F. Hourdin, M. Haeffelin, A. Mathieu, and C. Rio, Assessment of physical parameterizations using a global climate model with stretchable grid and nudging, Monthly Weather Review, vol.135, pp.1474-1489, 2007.

J. W. Deardorff, Preliminary results from numerical integrations of the unstable planetary boundary layer, Journal of Atmospheric Sciences, vol.27, pp.1209-1211, 1970.

D. P. Dee, S. M. Uppala, A. J. Simmons, P. Berrisford, P. Poli et al.,

F. Vitart, The ERA-Interim reanalysis: Configuration and performance of the data assimilation system, Quarterly Journal of the Royal Meteorological Society, vol.137, pp.553-597, 2011.

A. Ducharne and K. Laval, Influence of the Realistic Description of Soil Water-Holding Capacity on the Global Water Cycle in a GCM, Journal of Climate, vol.13, pp.4393-4413, 2000.

J. Dufresne, M. Foujols, S. Denvil, A. Caubel, O. Marti et al.,

N. Vuichard, Climate change projections using the IPSL-CM5 Earth System Model: From CMIP3 to CMIP5, Climate Dynamics, vol.40, pp.2123-2165, 2013.
URL : https://hal.archives-ouvertes.fr/hal-00794170

E. A. Eltahir and C. Gong, Dynamics of wet and dry years in West Africa, Journal of Climate, vol.9, pp.1030-1042, 1996.

K. A. Emanuel and M. Zivkovic-rothman, Development and evaluation of a convection scheme for use in climate models, Journal of Atmospheric Sciences, vol.56, pp.1766-1782, 1999.

Y. Fouquart and B. Bonnel, Computations of solar heating of the Earth's atmosphere: A new parametrization. Contributions to Atmospheric, Physics, vol.53, pp.35-62, 1980.

M. Gaetani, C. Flamant, S. Bastin, S. Janicot, C. Lavaysse et al., West African monsoon dynamics and precipitation: The competition between global SST warming and CO 2 increase in CMIP5 idealized simulations, Climate Dynamics, vol.48, pp.1353-1373, 2016.
URL : https://hal.archives-ouvertes.fr/insu-01309682

A. Giannini, X. Saravanan, and X. Chang, Ocean forcing of Sahel rainfall on interannual to interdecadal time-scales, Science, vol.302, pp.1027-1030, 2002.

J. Grandpeix, J. Lafore, and F. Cheruy, A density current parameterization coupled with Emanuel's Convection Scheme. Part II: 1D simulations, Journal of Atmospheric Sciences, vol.67, pp.898-922, 2010.
URL : https://hal.archives-ouvertes.fr/hal-01116769

J. Y. Grandpeix, V. Phillips, and R. Tailleux, Improved mixing representation in Emanuel's convection scheme, Quarterly Journal of the Royal Meteorological Society, vol.130, pp.3207-3222, 2004.

M. Grippa, L. Kergoat, A. Boone, C. Peugeot, J. Demarty et al., Modelling surface runoff and water fluxes over contrasted soils in pastoral Sahel: Evaluation of the ALMIP2 land surface models over the Gourma region in Mali, the ALMIP2 working group, vol.18, pp.1847-1866, 2016.

F. Guichard, L. Kergoat, F. Hourdin, C. L. Authaud, J. Barbier et al., , 2015.

F. Guichard, L. Kergoat, E. Mougin, F. Timouk, F. Baup et al., Surface thermodynamics and radiative budget in the Sahelian Gourma: Seasonal and diurnal cycles, Journal of Hydrology, vol.375, pp.161-177, 2009.
URL : https://hal.archives-ouvertes.fr/meteo-00340108

A. J. Heymsfield and L. J. Donner, A scheme for parameterizing ice-cloud water content in general circulation models, Journal of Atmospheric Sciences, vol.47, pp.1865-1877, 1990.

A. J. Heymsfield, G. Van-zadelhoff, D. P. Donovan, F. Fabry, R. J. Hogan et al., Refinements to ice particle mass dimensional and terminal velocity relationships for ice clouds. Part II: Evaluation and parameterizations of ensemble ice particle sedimentation velocities, Journal of Atmospheric Sciences, vol.64, p.1068, 2007.

F. Hourdin, F. Couvreux, and L. Menut, Parameterisation of the dry convective boundary layer based on a mass flux representation of thermals, Journal of Atmospheric Sciences, vol.59, pp.1105-1123, 2002.

F. Hourdin, M. Foujols, F. Codron, V. Guemas, J. Dufresne et al.,

L. Bopp, Impact of the LMDZ atmospheric grid configuration on the climate and sensitivity of the IPSL-CM5A coupled model, Climate Dynamics, vol.40, pp.2167-2192, 2013.
URL : https://hal.archives-ouvertes.fr/hal-01096296

F. Hourdin, J. Grandpeix, C. Rio, S. Bony, A. Jam et al.,

R. Roehrig, LMDZ5B: The atmospheric component of the IPSL climate model with revisited parameterizations for clouds and convection, Climate Dynamics, vol.40, pp.2193-2222, 2013.
URL : https://hal.archives-ouvertes.fr/hal-01098866

F. Hourdin, T. Mauritsen, A. Gettelman, J. Golaz, V. Balaji et al.,

D. Williamson, The Art and Science of Climate Model Tuning, Bulletin of the American Meteorological Society, vol.98, pp.589-602, 2017.

, Journal of Advances in Modeling Earth Systems

A. L. Diallo, . Gcm, . West, . In-situ, and . Data, GCM facing West Africa in-situ data, vol.27

F. Hourdin, I. Musat, F. Guichard, P. M. Ruti, F. Favot et al., AMMA-model intercomparison project, Bulletin of the American Meteorological Society, vol.91, p.95, 2010.
URL : https://hal.archives-ouvertes.fr/hal-00458342

A. Idelkadi, P. Levan, and F. Hourdin, A global climate model with strechable grid and nudging: I. Simulation of tracer transport at continental scales, Tech. Rep.). IPSL, 2005.

A. Jam, F. Hourdin, C. Rio, and F. Couvreux, Resolved versus parametrized boundary-layer plumes. Part III: Derivation of a statistical scheme for cumulus clouds, Boundary-Layer Meteorology, vol.147, pp.421-441, 2013.
URL : https://hal.archives-ouvertes.fr/hal-01099391

S. Janicot, C. D. Thorncroft, A. Ali, N. Asencio, G. Berry et al.,

A. Forecasters-team, Large-scale overview of the summer monsoon over West Africa during the AMMA field experiment in 2006, Annales Geophysicae, vol.26, pp.2569-2595, 2008.

G. Krinner, N. Viovy, N. De-noblet-ducoudr-e, J. Og-ee, J. Polcher et al.,

I. C. Prentice, A dynamic global vegetation model for studies of the coupled atmosphere-biosphere system, Global Biogeochemical Cycles, vol.19, 2005.
URL : https://hal.archives-ouvertes.fr/insu-00374606

C. Leauthaud, B. Cappelaere, J. Demarty, F. Guichard, C. Velluet et al., A 60-year reconstructed high-resolution local meteorological data set in Central Sahel (1950-2009): Evaluation, analysis and application to land surface modelling, EGU General Assembly Conference Abstracts, vol.19, p.11952, 2017.
URL : https://hal.archives-ouvertes.fr/hal-01630365

T. Lebel, B. Cappelaere, S. Galle, N. Hanan, L. Kergoat et al.,

L. Seguis, AMMA-CATCH studies in the Sahelian region of West-Africa: An overview, Journal of Hydrology, vol.375, pp.3-13, 2009.
URL : https://hal.archives-ouvertes.fr/ird-00392544

R. Locatelli, P. Bousquet, F. Hourdin, M. Saunois, A. Cozic et al.,

A. G. Williams, Atmospheric transport and chemistry of trace gases in LMDz5B: Evaluation and implications for inverse modelling, Geoscience Model Development, vol.8, pp.129-150, 2015.
URL : https://hal.archives-ouvertes.fr/hal-01806661

F. Lohou, L. Kergoat, F. Guichard, A. Boone, B. Cappelaere et al.,

F. Timouk, Surface response to rain events throughout the West African monsoon, Atmospheric Chemistry & Physics, vol.14, pp.3883-3898, 2014.
URL : https://hal.archives-ouvertes.fr/hal-00965406

F. Lott and M. Miller, A new sub-grid scale orographic drag parametrization: Its formulation and testing, Quarterly Journal of the Royal Meteorological Society, vol.123, pp.101-128, 1997.

O. Mamadou, J. M. Cohard, S. Galle, C. N. Awanou, A. Diedhiou et al., Energy fluxes and surface characteristics over a cultivated area in Benin: Daily and seasonal dynamics, Hydrology and Earth System Sciences, vol.18, pp.893-914, 2014.
URL : https://hal.archives-ouvertes.fr/hal-02046581

J. Morcrette, Radiation and cloud radiative properties in the European Centre for Medium Range Weather Forecasts forecasting system, Journal of Geophysical Research, vol.96, pp.9121-9132, 1991.

E. Mougin, V. Demarez, M. Diawara, P. Hiernaux, N. Soumaguel et al., Estimation of LAI, fAPAR and fCover of Sahel rangelands, vol.198, pp.155-167, 2014.

T. Murray and A. Verhoef, Moving towards a more mechanistic approach in the determination of soil heat flux from remote measurements, Agricultural and Forest Meteorology, vol.147, pp.88-97, 2007.

D. Ramier, N. Boulain, B. Cappelaere, F. Timouk, M. Rabanit et al.,

V. Wawrzyniak, Towards an understanding of coupled physical and biological processes in the cultivated Sahel -1. Energy and water, Journal of Hydrology, vol.375, pp.204-216, 2009.
URL : https://hal.archives-ouvertes.fr/insu-00413374

J. Redelsperger, C. D. Thorncroft, A. Diedhiou, T. Lebel, D. J. Parker et al., African Monsoon Multidisciplinary Analysis: An International Research Project and Field Campaign, Bulletin of the American Meteorological Society, vol.87, issue.12, 2006.
URL : https://hal.archives-ouvertes.fr/insu-00385875

C. Rio, J. Grandpeix, F. Hourdin, F. Guichard, F. Couvreux et al.,

A. Idelkadi, Control of deep convection by sub-cloud lifting processes: The ALP closure in the LMDZ5B general circulation model, Climate Dynamics, vol.40, pp.2271-2292, 2013.
URL : https://hal.archives-ouvertes.fr/hal-01092124

C. Rio and F. Hourdin, A thermal plume model for the convective boundary layer: Representation of cumulus clouds, Journal of Atmospheric Sciences, vol.65, pp.407-425, 2008.

C. Rio, F. Hourdin, F. Couvreux, and A. Jam, Resolved versus parametrized boundary-layer plumes. Part II: Continuous formulations of mixing rates for mass-flux schemes, Boundary-Layer Meteorology, vol.135, pp.469-483, 2010.
URL : https://hal.archives-ouvertes.fr/hal-01099391

C. Rio, F. Hourdin, J. Grandpeix, and J. Lafore, Shifting the diurnal cycle of parameterized deep convection over land, Geophysical Research Letters, vol.36, 2009.

R. Roehrig, D. Bouniol, F. Guichard, F. Hourdin, and J. Redelsperger, The present and future of the west african monsoon: A process-oriented assessment of cmip5 simulations along the amma transect, Climate Dynamics, vol.26, pp.6471-6505, 2013.
URL : https://hal.archives-ouvertes.fr/hal-01109027

R. Sadourny and K. Laval, January and July performance of the LMD General Circulation Model, New Perspectives in Climate Modelling, vol.13, pp.173-198, 1984.

O. Samain, L. Kergoat, H. Hiernaux, F. Guichard, E. Mougin et al., Analysis of the in situ and modis albedo variability at multiple time-scales in the Sahel, Journal of Geophysical Research, vol.113, 2008.
URL : https://hal.archives-ouvertes.fr/ird-00391544

I. Sandu, A. Beljaars, P. Bechtold, T. Mauritsen, and G. Balsamo, Why is it so difficult to represent stably stratified conditions in numerical weather prediction (NWP) models?, Journal of Advances in Modeling Earth Systems, vol.5, pp.117-133, 2013.

C. G. Schmitt and A. J. Heymsfield, The Size Distribution and Mass-Weighted Terminal Velocity of Low-Latitude Tropopause Cirrus Crystal Populations, Journal of Atmospheric Sciences, vol.66, 2009.

J. J. Settle, N. A. Bharmal, G. J. Robinson, and A. Slingo, Sampling uncertainties in surface radiation budget calculations in RADAGAST, Journal of Geophysical Research, vol.113, 2008.

A. Slingo, H. E. White, N. A. Bharmal, and G. J. Robinson, Overview of observations from the RADAGAST experiment in Niamey, Niger: 2. Radiative fluxes and divergences, Journal of Geophysical Research, vol.114, 2009.

T. Stocker, G. D. Qin, M. Plattner, S. Tignor, J. Allen et al.,

, IPCC, 2013: Climate change 2013: The physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change (1535 pp.), 2013.

C. M. Taylor, A. Gounou, F. Guichard, P. P. Harris, R. J. Ellis et al., Frequency of Sahelian storm initiation enhanced over mesoscale soil-moisture patterns, Nature Geoscience, vol.4, pp.430-433, 2011.

F. Timouk, L. Kergoat, E. Mougin, C. R. Lloyd, E. Ceschia et al.,

C. M. Taylor, Response of surface energy balance to water regime and vegetation development in a Sahelian landscape, Journal of Hydrology, vol.375, pp.178-189, 2009.
URL : https://hal.archives-ouvertes.fr/ird-00392519

E. A. Tsvetsinskaya, C. B. Schaaf, F. Gao, A. H. Strahler, R. E. Dickinson et al., Relating MODIS-derived surface albedo to soils and rock types over Northern Africa and the Arabian peninsula, Journal of Geophysical Research, vol.29, issue.9, p.1353, 2002.

, Impact des poussières interactives

, 16 -Coupe latitudinale-temps de la différence du flux solaire arrivant à la surface ( SW in , en W/m 2 , a) et infra-rouge arrivant à la surface ( LW in , en W/m 2 , b) entre les simulations INTER et CLEAN, moyennée entre 10 ? W et 10 ? E. Ces résultats sont montrés sur deux graphiques de différentes palettes, l'une pour la zone sahélienne, SW in (en W/m 2 ) INTER-CLEAN b) LW in (en W/m 2 ) INTER-CLEAN FIGURE 4

, Tout comme dans le SW, l'ARE dans le LW est maximum aux environ de 15 ? N et est de l'odre de 13-17 ? N. En été

P. Dans-cette, Avec l'introduction des poussières interactives, la représentation du SW net est légèrement améliorée dans le modèle. Cependant, à cause des biais sur les valeurs de l'albédo de surface (voir chapitre 3 figure 3.3) mais également des biais de surestimation restant sur le SW in , le SW net reste surestimé notamment au mois de juin en zone sahélienne et en hiver en zone soudanienne. L'augmentation du LW in au printemps par les poussières induit une augmentation du LW net dans la simulation INTER car le LW up reste pratiquement inchangé (non montré), nous cherchons tout d'abord à déterminer l'effet des poussières interactives sur le rayonnement net

, En conséquence de ces résultats, la surestimation du R net n'est que légèrement réduite. Ainsi, malgré l'introduction des poussières interactives et un impact généralement très positif sur les flux incidents, le a) SW (en W/m 2 ) MAM b) SW (en W/m 2 ) JAS de mars-avril-mai (MAM, à gauche) et juillet-août-septembre

, T 2m , en ? C, a) et des températures (en ? C) minimales et maximales (respectivement Tmin et Tmax, b)de l'année 2006 aux stations de Bamba, Agoufou, Wankama, Nalohou et Bira (respectivement de haut en bas). Les données d'observations insitu (noir) sont comparées aux sorties des simulations PRESCR (rouge)

, 24 -Carte du flux solaire arrivant à la surface ( SW in , en W/m 2 ) moyenné sur le mois d'avril 2010 (à gauche) et son anomalie par rapport à une moyenne sur 2000-2013 (à droite) dans, SW in (en W/m 2 ) avril 2010 moyenné SW in (en W/m 2 ) avril 2010 anomalie FIGURE 4

, 25 -Carte du flux infra-rouge arrivant à la surface ( LW in , en W/m 2 ) moyenné sur le mois d'avril 2010 (à gauche) et son anomalie par rapport à une moyenne sur 2000-2013 (à droite) dans, LW in (en W/m 2 ) avril 2010 moyenné LW in (en W/m 2 ) avril 2010 anomalie FIGURE 4

, Tmax (en ? C) avril 2010 moyennée Tmax (en ? C) avril 2010 anomalie

Y. Largeron,

, 26 -Carte de la température à 2 m maximale (Tmax, en ? C) moyennée sur le mois d'avril 2010 (à gauche) et son anomalie par rapport à une moyenne sur, 2000.

, Malgré le guidage le modèle présente également des biais sur PRW. Ces biais vont induire à leur tour des biais sur les flux et les températures notamment au centre nord du Sahel. La vague de chaleur d'avril 2010 n'est donc pas bien représentée dans le modèle. Néanmoins, en comparaison à la moyenne climatologique, le modèle arrive à détecter des anomalies légèrement positives de Tmin et Tmax d'un ordre de grandeur assez cohérent avec les observations. Nous avons vu dans l'analyse du PRW, que même en guidant le vent, le PRW peut s'avérer être différent suivant que la simulation est effectuée avec poussières interactives ou avec poussières prescrites. Or, l'augmentation du PRW au Sahel a été identifiée comme un facteur clé ayant favorisé la vague de chaleur de 2010. Aussi, nous nous sommes demandés quel était l'effet des aérosols sur le PRW au Sahel, le mois d'avril 2010 en moyenne est mieux représenté avec les poussières interactives notamment sur le Sahel. Cependant, durant ce mois le modèle rate des événements de poussières

, V10m (en m/s) & PRW (en cm) INTER

, V10m (en m/s) & AOD INTER-CLEAN

. Prw-inter-clean,

, en cm) et vent à 10m (en m/s) moyennés sur le mois d'avril 2010 dans la simulation INTER. Les graphiques b et c présentent des cartes de la différence de la moyenne sur le mois d'avril 2010 : de l'eau précipitable en cm (PRW, b), du vent à 10m en /s et de la profondeur optique des aérosols (V10m & AOD, c) entre la simulation INTER et CLEAN. Graphique d : coupe latitude-verticale de la différence de la moyenne en avril 2010 du vent (V, en m/s) et de la température (T, en ? C) entre les simulations INTER et CLEAN. a)

, 30 -Cartes de la différence de la moyenne sur 2000-2013 sur juillet-Août-Septembre (JAS) : de l'eau précipitable (en cm, PRW, a), de la température à 2m et minimale (en ? C, respectivement T 2m , graphique b et Tmin, graphique c), de la précipitation, /mois) INTER-CLEAN d) Tmin INTER-CLEAN FIGURE 4

, maximale (Tmax) et moyenne ( T 2m ) moyennes sur le mois d'avril et en moyenne sur une boite couvrant la zone sahélienne, FIGURE 4.31 -Évolution inter-annelle entre 2000 et 2013 de la température (en ? C) minimale (Tmin)

, Nous constatons que les résultats de l'effet des aérosols en couplage avec la dynamique du modèle sont assez similaires de ceux vus en configuration guidée. En avril, la présence d'aérosols dans l'atmosphère contribue, par rétroaction sur la circulation (voir figure 4.34 a et c), à augmenter le PRW mais plus à l'est de la région que dans la simulation guidée et de manière plus intense sur le Nigeria (voir figure 4.32), Les résultats des analyses de cette étude sont montrés sur les figures 4.32 pour le mois d'avril et 4.33 pour l'été (juillet-août-septembre)

, PRW (en cm) REG-INTER -REG-CLEAN b) T 2m ( en ? C) REG-INTER -REG-CLEAN

, 33 -Cartes de la différence de la moyenne sur 2000-2013 sur juillet-août-septembre (JAS) : de l'eau précipitable (en cm, PRW, a), de la température à 2m et minimale (en ? C, respectivement T 2m , graphique b et Tmin, graphique d), de la précipitation (en mm/mois, précip, c) entre les moyennes de simulations REG, /mois) REG-INTER -REG-CLEAN d) Tmin REG-INTER -REG-CLEAN FIGURE 4

R. ,

, V (en m/s) & T (en ? C) sur avril

, V (en m/s) & T (en ? C) sur JAS

. V10m, 34 -Les graphiques (a,b c et d) représentent des différences de la moyenne de 6 séries sur 2000-2013 de simulations entre REG-INTet REG-CLEAN. Les graphiques a et b montrent respectivement des coupes latitude-verticale de la moyenne sur avril et sur JAS (juillet-août-septembre) du vent (V, en m/s) et de la température (T,en ? C) . Les graphiques c et d montrent respectivement des cartes moyennes sur avril et sur JAS (juillet-août-septembre) du vent à 10 m (en m/s, V10m), AOD sur avril d) V10m (en m/s) & AOD sur JAS FIGURE 4

, autres vagues de chaleur où les valeurs d'AOD (profondeur optique des aérosols) seraient mieux

R. F. Adler, G. J. Huffman, A. Chang, R. Ferraro, P. Xie et al., The version-2 global precipitation climatology project (gpcp) monthly precipitation analysis (1979 present), Journal of Hydrometeorology, vol.4, p.1147, 2003.

E. E. Ago, E. K. Agbossou, P. Ozer, A. , and M. , Mesure des flux de CO2 et séquestration de carbone dans les écosystèmes terrestres ouest-africains, 2015.

S. Aït-mesbah, J. L. Dufresne, F. Cheruy, and F. Hourdin, The role of thermal inertia in the representation of mean and diurnal range of surface temperature in semiarid and arid regions, Geophys. Res. Lett, vol.42, pp.7572-7580, 2015.

M. O. Andreae and P. J. Crutzen, Atmospheric Aerosols : Biogeochemical sources and role in atmospheric chemistry, 1998.

A. P. Baede, Glossaires des contributions des Groupes de travail I, 2007.

J. Barbier, F. Guichard, D. Bouniol, F. Couvreux, and R. Roehrig, Spring sahelian heatwaves : detection, characteristics and historical trend, In preparation for Journal of Climate, 2017.

F. Beucher, Manuel de météorologie tropicalel des alizés au cyclone tropical, vol.2, 2010.

N. L. Bindoff, P. A. Stott, K. M. Achutarao, M. R. Allen, N. Gillett et al., Chapter 10 -detection and attribution of climate changel from global to regional, Climate Change 2013l The Physical Science Basis. IPCC Working Group I Contribution to AR5, 2013.

A. K. Blackadar, Boundary-layer wind maxima and their significance for the growth of nocturnal inversions, Bull. Am. Meteorol. Soc, 1957.

S. Bony and K. A. Emanuel, A parameterization of the cloudiness associated with cumulus convection ; evaluation using TOGA COARE data, J. Atmos. Sci, vol.58, pp.3158-3183, 2001.

D. Bou-karama, Mécanismes de soulèvement d'aérosols désertiques en Afrique de l'Ouest, 2008.

D. L. Cadet and N. O. Nnoli, Water vapour transport over Africa and the Atlantic Ocean during summer 1979, Quarterly Journal of the Royal Meteorological Society, vol.113, pp.581-602, 1987.

R. V. Cakmur, R. L. Miller, and O. Torres, Incorporating the effect of small-scale circulations upon dust emission in an atmospheric general circulation model, J. Geophys. Res, vol.109, p.7201, 2004.

Y. Callot, C. Mering, and A. Simonin, Image-analysis and cartography of sand hill massifs on high resolution images l application to the Great Western Erg (NW of Algerian Sahara), International Journal of Remote Sensing, vol.15, pp.3799-3822, 1994.

B. Chatenet, B. Marticorena, L. Gomes, and G. Bergametti, Assessing the microped size distributions of desert soils erodible by wind, Sedimentology, vol.43, pp.901-911, 1996.

A. Chevalier, Le territoire geobotanique de l'Afrique tropicale nord-occidentale et les divisions, 1933.

K. H. Cook, Generation of the African Easterly Jet and Its Role in Determining West African Precipitation, Journal of Climate, vol.12, pp.1165-1184, 1999.

P. De-rosnay, M. Bruen, and J. Polcher, Sensitivity of surface fluxes to the number of layers in the soil model used in GCMs, 2000.

P. De-rosnay and J. Polcher, Modelling root water uptake in a complex land surface scheme coupled to a GCM, Hydrology and Earth System Sciences, vol.2, 1998.
URL : https://hal.archives-ouvertes.fr/hal-00330830

J. W. Deardorff, Preliminary results from numerical integrations of the unstable planetary boundary layer, J. Atmos. Sci, vol.27, pp.1209-1211, 1970.

F. B. Diallo, F. Hourdin, C. Rio, A. Traore, L. Mellul et al., The surface energy budget computed at the grid-scale of a climate model challenged by station data in west africa, Journal of Advances in Modeling Earth Systems, vol.9, issue.7, pp.2710-2738, 2017.
URL : https://hal.archives-ouvertes.fr/hal-01696565

T. D'orgeval, Imapct du changement climatique sur le cycle de l'eau en afrique de l'Ouest : Modélisation et incertitudes, p.172, 2006.

N. I. Ducoudré, K. Laval, and A. Perrier, SECHIBA, a New Set of Parameterizations of the Hydrologic Exchanges at the Land-Atmosphere Interface within the LMD Atmospheric General Circulation Model, Journal of Climate, vol.6, pp.248-273, 1993.

J. Dufresne, M. Foujols, S. Denvil, A. Caubel, O. Marti et al., , vol.40, pp.2123-2165, 2013.

K. S. Edjame and ;. Guinee, , 2007.

E. A. Eltahir and C. Gong, Dynamics of Wet and Dry Years in West Africa, Journal of Climate, vol.9, pp.1030-1042, 1996.

K. A. Emanuel and M. Zivkovic-rothman, Development and Evaluation of a Convection Scheme for Use in Climate Models, J. Atmos. Sci, vol.56, pp.1766-1782, 1999.

J. Escribano, O. Boucher, F. Chevallier, and N. Huneeus, Subregional inversion of North African dust sources, Journal of Geophysical Research (Atmospheres), vol.121, pp.8549-8566, 2016.
URL : https://hal.archives-ouvertes.fr/hal-01366496

. Fao, Soil Map of the World, 1978.

. Fao, THE STATE OF FOOD AND AGRICULTIURE, 1984.

D. A. Faysash and E. A. Smith, Simultaneous Land Surface Temperature Emissivity Retrieval in the Infrared Split Window, Journal of Atmospheric and Oceanic Technology, vol.16, p.1673, 1999.

H. Flohn, D. Henning, and H. C. Korff, studies on the water-vapour transport over northern Africa, 1965.

B. Fontaine and S. Janicot, Wind-Field Coherence and Its Variations over West Africa, Journal of Climate, vol.5, pp.512-524, 1992.

Y. Fouquart and B. Bonnel, Computations of solar heating of the Earth's atmospherel A new parametrization. bpa, vol.53, pp.35-62, 1980.

A. Giannini, X. Saravanan, C. , and X. , Ocean forcing of sahel rainfall on interannual to interdecadal time-scales, Science, vol.302, pp.1027-1030, 2002.

J. Grandpeix, J. Lafore, and F. Cheruy, A Density Current Parameterization Coupled with Emanuel's Convection Scheme. Part IIl 1D Simulations, Journal of Atmospheric Sciences, vol.67, pp.898-922, 2010.
URL : https://hal.archives-ouvertes.fr/hal-01116769

M. ;. Gueye, . Modelisation, . Couplages, . Les, . Desertiques et al., , 2014.

F. Guichard, L. Kergoat, F. Hourdin, C. Léauthaud, J. Barbier et al., , 2015.

, Le réchauffement climatique observé depuis 1950 au Sahel

R. A. Hamilton and J. W. Archibald, Meteorology of Nigeria and adjacent territory, 1945.

B. Heese and M. Wiegner, Vertical aerosol profiles from Raman polarization lidar observations during the dry season AMMA field campaign, Journal of Geophysical Research (Atmospheres), vol.113, pp.0-11, 2008.

G. C. Hegerl, T. J. Crowley, M. Allen, W. T. Hyde, H. N. Pollack et al., Detection of Human Influence on a New, Validated 1500-Year Temperature Reconstruction, Journal of Climate, vol.20, p.650, 2007.

F. Hourdin, F. Couvreux, and L. Menut, Parameterisation of the dry convective boundary layer based on a mass flux representation of thermals, J. Atmos. Sci, vol.59, pp.1105-1123, 2002.

F. Hourdin, M. Gueye, B. Diallo, J. Dufresne, J. Escribano et al., Parameterization of convective transport in the boundary layer and its impact on the representation of the diurnal cycle of wind and dust emissions, Atmosph. Chemist. and Physics, vol.15, pp.6775-6788, 2015.

F. Hourdin, A. G?inus?-bogdan, P. Braconnot, J. Dufresne, A. Traore et al., Air moisture control on ocean surface temperature, 2015.
URL : https://hal.archives-ouvertes.fr/hal-01805157

F. Hourdin, I. Musat, F. Guichard, P. M. Ruti, F. Favot et al., AMMA-Model Intercomparison Project, Bulletin of the American Meteorological Society, vol.91, p.95, 2010.
URL : https://hal.archives-ouvertes.fr/hal-00458342

G. J. Huffman, R. F. Adler, M. M. Morrissey, D. T. Bolvin, S. Curtis et al., Global Precipitation at One-Degree Daily Resolution from Multisatellite Observations, Journal of Hydrometeorology, vol.2, p.36, 2001.

N. Huneeus, O. Boucher, and F. Chevallier, Simplified aerosol modeling for variational data assimilation, Geoscientific Model Development, vol.2, pp.213-229, 2009.

S. Janicot, G. Caniaux, F. Chauvin, G. De-coëtlogon, B. Fontaine et al., Intraseasonal variability of the West African monsoon, Atmospheric Science Letters, vol.12, pp.58-66, 2011.
URL : https://hal.archives-ouvertes.fr/hal-00548109

A. Joseph, J. P. Frangi, and J. F. Aranyossy, Isotope Characteristics of Meteoric Water and Groundwater in the Sahelo-Sudanese zone, JOURNAL OF GEOPHYSICAL RESEARCH, 1979.

J. T. Kiehl and K. E. Trenberth, Earth's Annual Global Mean Energy Budget, Bulletin of the American Meteorological Society, vol.78, pp.197-197, 1997.

G. Krinner, N. Viovy, N. De-noblet-ducoudré, J. Ogée, J. Polcher et al., A dynamic global vegetation model for studies of the coupled atmosphere-biosphere system, Global Biogeochemical Cycles, vol.19, p.1015, 2005.
URL : https://hal.archives-ouvertes.fr/insu-00374606

Y. Largeron, F. Guichard, D. Bouniol, F. Couvreux, L. Kergoat et al., Can we use surface wind fields from meteorological reanalyses for sahelian dust emission simulations ?, Geophysical Research Letters, vol.42, issue.7, pp.2490-2499, 2015.

Y. Largeron, F. Guichard, R. Roehrig, F. Couvreux, and J. Barbier, , 2010.

C. Lavaysse, C. Flamant, A. Evan, S. Janicot, and M. Gaetani, Recent climatological trend of the Saharan heat low and its impact on the West African climate, Climate Dynamics, vol.47, pp.3479-3498, 2016.
URL : https://hal.archives-ouvertes.fr/insu-01208169

T. Lebel, B. Cappelaere, S. Galle, N. Hanan, L. Kergoat et al., AMMA-CATCH studies in the Sahelian region of West-Africal An overview, Journal of Hydrology, vol.375, pp.3-13, 2009.

T. Lebel, L. Barbé, and L. , Rainfall monitoring during HAPEX-Sahel. 2. Point and areal estimation at the event and seasonal scales, Journal of Hydrology, vol.188, pp.97-122, 1997.

Z. Li, Ensemble Atmospheric GCM Simulation of Climate Interannual Variability from 1979 to 1994, J. Climate, vol.12, pp.986-1001, 1999.

C. Liousse, M. O. Andreae, P. Artaxo, P. Barbosa, J. M. Grégoire et al., Deriving Global Quantitative Estimates for Spatial and Temporal Distributions of Biomass Burning Emissions, 2004.

F. Lott and M. Miller, A new sub-grid scale orographic drag parametrizationl its formulation and testing, Q. J. R. Meteorol. Soc, vol.123, pp.101-128, 1997.

C. Ma, C. R. Mechoso, A. W. Robertson, A. , and A. , Peruvian Stratus Clouds and the Tropical Pacific Circulationl A Coupled Ocean-Atmosphere GCM Study, Journal of Climate, vol.9, pp.1635-1645, 1996.

N. M. Mahowald, A. R. Baker, G. Bergametti, N. Brooks, R. A. Duce et al., Atmospheric global dust cycle and iron inputs to the ocean, Global Biogeochemical Cycles, vol.19, p.4025, 2005.
URL : https://hal.archives-ouvertes.fr/hal-02326052

F. Malavelle, Effets direct et semi-direct des aérosols en Afrique de l'ouest pendant la saison sèche, 2011.

B. Marticorena and G. Bergametti, Modeling the atmospheric dust cyclel 1. Design of a soil-derived dust emission scheme. jgr, p.100, 1995.

G. M. Martin, P. Peyrillé, R. Roehrig, C. Rio, M. Caian et al., Understanding the West African Monsoon from the analysis of diabatic heating distributions as simulated by climate models, Journal of Advances in Modeling Earth Systems, vol.9, pp.239-270, 2017.
URL : https://hal.archives-ouvertes.fr/hal-01507050

E. Matthews, Global Vegetation and Land Usel New High-Resolution Data Bases for Climate Studies, Journal of Applied Meteorology, vol.22, pp.474-487, 1983.

G. A. Meehl, J. M. Arblaster, and C. Tebaldi, Understanding future patterns of increased precipitation intensity in climate model simulations, 2005.

L. Menut, R. Vautard, M. Beekmann, and C. Honoré, Sensitivity of photochemical pollution using the adjoint of a simplified chemistry-transport model, J. Geophys. Res, vol.105, pp.15379-15402, 2000.

E. J. Mlawer, S. J. Taubman, P. D. Brown, M. J. Iacono, and S. A. Clough, Radiative transfer for inhomogeneous atmospheresl RRTM, p.102, 1997.

J. Morcrette, Radiation and cloud radiative properties in the European Centre for Medium Range Weather Forecasts forecasting system. jgr, vol.96, pp.9121-9132, 1991.

V. Moron, B. Oueslati, B. Pohl, S. Rome, J. et al., Trends of mean temperatures and warm extremes in northern tropical africa (1961-2014) from observed and ppca-reconstructed time series, vol.121, pp.5298-5319, 2016.
URL : https://hal.archives-ouvertes.fr/hal-02895206

S. E. Nicholson and J. P. Grist, A conceptual model for understanding rainfall variability in the West African Sahel on interannual and interdecadal timescales, International Journal of Climatology, vol.21, pp.1733-1757, 2001.

S. E. Nicholson and J. C. Selato, The influence of La Nina on African rainfall, International Journal of Climatology, vol.20, pp.1761-1776, 2000.

S. E. Nicholson, B. Some, and B. Kone, An Analysis of Recent Rainfall Conditions in West Africa, Including the Rainy Seasons of the 1997 El Niño and the 1998 La Niña Years, Journal of Climate, vol.13, pp.2628-2640, 2000.

B. Oueslati, B. Pohl, V. Moron, and S. Rome, Characterization of Heat Waves in the Sahel and associated mechanisms, vol.18, pp.2016-2834, 2016.
URL : https://hal.archives-ouvertes.fr/halshs-02153194

G. Panthou, T. Vischel, and T. Lebel, Recent trends in the regime of extreme rainfall in the central sahel, International Journal of Climatology, issue.15, p.34, 2014.

M. Parry, O. Canziani, J. Palutikof, J. Van-der-linden, H. et al., Climate change 2007. impacts, adaptation and vulnerability. contribution of working group ii to the fourth assessment report of the intergovernmental panel on climate change, p.976, 2007.

M. C. Peel, B. L. Finlayson, and T. A. Mcmahon, Updated world map of the Köppen-Geiger climate classification, Hydrology and Earth System Sciences, vol.11, pp.1633-1644, 2007.

H. L. Penman, Estimating evaporation, Transactions, vol.37, pp.43-50, 1956.

P. Peyrillé and J. Lafore, An Idealized Two-Dimensional Framework to Study the West African Monsoon. Part IIl Large-Scale Advection and the Diurnal Cycle, Journal of Atmospheric Sciences, vol.64, p.2783, 2007.

P. Peyrillé, J. Lafore, and J. Redelsperger, An Idealized Two-Dimensional Framework to Study the West African Monsoon. Part Il Validation and Key Controlling Factors, Journal of Atmospheric Sciences, vol.64, p.2765, 2006.

R. Pilon, Transport et élimination des radionucléïdes naturels par les processus nuageux : Mécanismes et représentation dans un modèle de climat, 2013.

C. S. Ramage, Monsoon Meteorology, pp.1-296, 1971.

J. Redelsperger, C. D. Thorncroft, A. Diedhiou, T. Lebel, D. J. Parker et al., , 2006.

, African Monsoon Multidisciplinary Analysisl An International Research Project and Field Campaign, Bulletin of the American Meteorological Society, vol.87, p.1739

C. Rio, J. Grandpeix, F. Hourdin, F. Guichard, F. Couvreux et al., Control of deep convection by sub-cloud lifting processesl the ALP closure in the LMDZ5B general circulation model, Clim. Dyn, vol.40, pp.2271-2292, 2013.

C. Rio and F. Hourdin, A thermal plume model for the convective boundary layer l representation of cumulus clouds, J. Atmos. Sci, vol.65, pp.407-425, 2008.

C. Rio, F. Hourdin, J. Grandpeix, and J. Lafore, Shifting the diurnal cycle of parameterized deep convection over land, Geophys. Res. Lett, vol.36, p.7809, 2009.

N. Rochetin, F. Couvreux, J. Grandpeix, and C. Rio, Deep convection triggering by boundary-layer thermals. Part Il LES analysis and stochastic triggering formulation, JAS, p.71, 2014.
URL : https://hal.archives-ouvertes.fr/hal-01083240

N. Rochetin, J. Grandpeix, C. Rio, and F. Couvreux, Deep convection triggering by boundary-layer thermals. Part IIl Stochastic triggering parameterization for the LMDZ GCM, JAS, p.71, 2014.
URL : https://hal.archives-ouvertes.fr/hal-01083240

R. Roehrig, D. Bouniol, F. Guichard, F. Hourdin, and J. Redelsperger, The present and future of the West African monsoonl a process-oriented assessment of CMIP5 simulations along the AMMA transect, Clim. Dyn, vol.26, pp.6471-6505, 2013.

T. Rossby, The Distribution of Angular Velocity in Gaseous Envelopes under Influence of Large-Scale Horizontal Mixing Processes, pp.53-68, 1947.

R. Sadourny and K. Laval, January and July performance of the LMD General Circulation Model, New Perspectives in Climate Modelling, vol.13, pp.173-198, 1984.

K. Saha, Tropical Circulation Systems and Monsoons, 2010.

K. Schepanski, I. Tegen, M. C. Todd, B. Heinold, G. Bönisch et al., Meteorological processes forcing Saharan dust emission inferred from MSG-SEVIRI observations of subdaily dust source activation and numerical models, Journal of Geophysical Research, vol.114, issue.D13, p.10201, 2009.

J. Sheffield and E. F. Wood, Projected changes in drought occurrence under future global warming from multi-model, multi-scenario, IPCC AR4 simulations, Climate Dynamics, vol.1, pp.79-105, 2008.

S. Sitch, B. Smith, I. C. Prentice, A. Arneth, A. Bondeau et al., Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the lpj dynamic global vegetation model, Global Change Biology, vol.9, issue.2, pp.161-185, 2003.
URL : https://hal.archives-ouvertes.fr/hal-01757605

M. V. Bibliographie-sivakumar, Agroclimatic Aspects of Rainfed Agriculture in the Sudano-Sahelian Zone, 1989.

A. Slingo, H. E. White, N. A. Bharmal, R. , and G. J. , Overview of observations from the radagast experiment in niamey, nigerl 2. radiative fluxes and divergences, J. Geophys. Res, vol.114, issue.D00E04, 2009.

T. Stocker, D. Qin, G. Plattner, M. Tignor, S. Allen et al., IPCC, 2013l Climate Change 2013l The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, p.1535, 2013.

Z. Su, T. Schmugge, W. P. Kustas, and W. J. Massman, An Evaluation of Two Models for Estimation of the Roughness Height for Heat Transfer between the Land Surface and the Atmosphere, Journal of Applied Meteorology, vol.40, pp.1933-1951, 2001.

B. Sultan and S. Janicot, The West African Monsoon Dynamics. Part IIl The 'Preonset' and 'Onset' of the Summer Monsoon, Journal of Climate, vol.16, pp.3407-3427, 2003.
URL : https://hal.archives-ouvertes.fr/hal-00155510

B. Sultan, S. Janicot, and P. Drobinski, Characterization of the diurnal cycle of the west african monsoon around the monsoon onset, Journal of Climate, vol.20, issue.15, pp.4014-4032, 2007.
URL : https://hal.archives-ouvertes.fr/hal-00194352

S. Szopa, Y. Balkanski, M. Schulz, S. Bekki, D. Cugnet et al., Aerosol and ozone changes as forcing for climate evolution between 1850 and 2100, Climate Dynamics, vol.40, pp.2223-2250, 2013.
URL : https://hal.archives-ouvertes.fr/hal-00723730

I. Tegen, K. Schepanski, and B. Heinold, Comparing two years of Saharan dust source activation obtained by regional modelling and satellite observations, Atmospheric Chemistry & Physics, vol.13, pp.2381-2390, 2013.

C. D. Thorncroft and M. Blackburn, Maintenance of the african easterly jet, Quarterly Journal of the Royal Meteorological Society, vol.125, issue.555, pp.763-786, 1999.

. Van-genuchten, A closed-form equation for predicting the hydraulic conductivity of unsaturated soils, vol.40, pp.892-898, 1980.

E. Vignon, F. Hourdin, C. Genthon, H. Gallée, E. Bazile et al., Antarctic boundary layer parametrization in a general circulation modell 1-d simulations facing summer observations at dome c, Journal of Geophysical Researchl Atmospheres, vol.122, issue.13, pp.6818-6843, 2017.

P. J. Webster, The Elementary Monsoon. Monsoons (Ed. IS Fein and PL Stephens), 1987.

T. Yamada, Simulations of nocturnal drainage flows by a q 2 l turbulence closure model, J. Atmos. Sci, vol.40, pp.91-106, 1983.

C. S. Zender, R. L. Miller, and I. Tegen, Quantifying mineral dust mass budgetslTerminology, constraints, and current estimates, EOS Transactions, vol.85, pp.509-512, 2004.

L. Zobler, A world soil file for global climate modeling, NASA tech.Memo, vol.87802, 1986.