PROGRAMME BLANC

EDITION 2010

Projet XXX

DOCUMENT SCIENTIFIQUE

Acronyme DECAF

Titre du projet en français

Rôle des processus couplés atmosphère/surface dans les variations DECennales de la mousson Ouest-AFricaine

Titre du projet en anglais

Rôle of coupled atmosphere/surface processes in the DECadal variations of the West-AFircan monssoon

Comité d’Evaluation référence (CE)1 SIM6

Projet multidisciplinaire

OUI x NONSi oui, indiquer l’intitulé du second CE

Coopération internationale (si applicable)

Le projet propose une coopération internationale avec les Etats-Unis (accord ANR/NSF)x autres pays

Aide totale demandée

xxxxxx € Durée du projet 36 mois

SOMMAIRE

1. CONTEXTE ET POSITIONNEMENT DU PROJET / CONTEXT AND POSITIONNING OF THE PROPOSAL .. 3 2. DESCRIPTION SCIENTIFIQUE ET TECHNIQUE / SCIENTIFIC AND TECHNICAL DESCRIPTION .......... 5

2.1. État de l'art / Background, state of the art ...................................................... 5 2.2. Objectifs et caractère ambitieux/novateur du projet / Rationale highlighting

the originality and novelty of the proposal .................................................. 8 3. PROGRAMME SCIENTIFIQUE ET TECHNIQUE, ORGANISATION DU PROJET / SCIENTIFIC AND

TECHNICAL PROGRAMME, PROJECT MANAGEMENT ............................................... 10 3.1. Programme scientifique et structuration du projet / scientific programme,

specific aims of the proposal ..................................................................... 10 3.2. Coordination du projet / project management ............................................... 12 3.3. Description des travaux par tâche / detailed description of the work

organised by tasks .................................................................................... 12 3.3.1 Tâche 1 / task 1 Evaluation of climate models and climate change simulations 12 3.3.2 Task 2 : Analyse of coupled atmosphere/surface processes from the “interface

variables” 14 3.3.3 Task 3 : Analyse of decadal climate variations of the seasonal cycle of rainfall in

Sahel. 14 3.3.4 Task 4 : Representation of interface variables and exploration of the role of

coupled atmosphere/surface processes in numerical models 15 3.4. Calendrier des tâches, livrables et jalons / planning of tasks, deliverables and

milestones ................................................................................................ 17

1 Indiquer la référence du CE choisi pour l’évaluation du projet (cf. tableaux page 3 et 4 du texte de l’appel à projets)

1/22

PROGRAMME BLANC

EDITION 2010

Projet XXX

DOCUMENT SCIENTIFIQUE

4. STRATÉGIE DE VALORISATION DES RÉSULTATS ET MODE DE PROTECTION ET D’EXPLOITATION DES RÉSULTATS / DATA MANAGEMENT, DATA SHARING, INTELLECTUAL PROPERTY AND RESULTS EXPLOITATION ...................................................................................... 18

5. ORGANISATION DU PARTENARIAT / CONSORTIUM ORGANISATION AND DESCRIPTION ............ 18 5.1. Description, adéquation et complémentarité des partenaires / relevance and

complementarity of the partners within the consortium ........................... 18 5.2. Qualification du coordinateur du projet / qualification of the project

coordinator ............................................................................................... 19 5.3. Qualification, rôle et implication des participants / contribution and

qualification od each project particpant .................................................... 19 6. JUSTIFICATION SCIENTIFIQUE DES MOYENS DEMANDÉS / SCIENTIFIC JUSTIFICATION OF REQUESTED

BUDGET ............................................................................................ 19 6.1. Partenaire 1 / partner 1 : XXX ........................................................................ 20 6.2. Partenaire 2 / partner 2 : XXX ........................................................................ 20

7. ANNEXES ............................................................................................ 20 7.1. Références bibliographiques / references ...................................................... 20 7.2. Biographies / CV, Resume .............................................................................. 22 7.3. Implication des personnes dans d’autres contrats / involvement of project

participants to other grants, contracts, etc … ........................................... 22

2/22

Avant de soumettre ce document :

- Supprimer toutes les instructions en rouge (par exemple en faisant Format Styles Menu contextuel du style « Instructions » Sélectionner toutes les occurrences suppr.)

- Mettre la table des matières à jour (bouton droit sur la table des matières mettre à jour les champs Mettre à jour toute la table).

- Donner toutes les références bibliographiques en annexe 7.1.

1. CONTEXTE ET POSITIONNEMENT DU PROJET / CONTEXT AND POSITIONNING OF THE PROPOSAL

(2 pages maximum)

Présentation générale du problème qu’il est proposé de traiter dans le projet et du cadre de travail

Préciser plus particulièrement le :

- positionnement du projet par rapport au contexte : vis-à-vis des projets et recherches antérieurs, concurrents ou complémentaires, des brevets et standards…

- Indiquer si le projet s’inscrit dans la continuité de projet(s) antérieurs déjà financés par l’ANR. Dans ce cas, présenter brièvement les résultats acquis.

-

- positionnement du projet aux niveaux européen et international,

- éventuels enjeux sociétaux, économiques, environnementaux, ….

The sahelian drought.

The Sahel, the transition region between the wet tropical climate of the coast of Gulf of Guinea and the Sahara desert, is the region of the planet that has undergone the largest modifications of its rainfall regime during the last decades. The severe drougth of the 70s and 80s had huge consequences on the local eco-systems and societies. The explanation for this strong climate decadal variation is still an open question and is at the heart of this proposal.

Impact of global warming

Fig 1 : Evolution of the summer rainfall in the CMIP3 (IPCC-AR4) climate change simulations. There is a general reinforcement of the contrasts in the tropics with

drier subtroical anti-cyclonic band (red) and a moister (blue) intertropical zone.

The future evolution of climate under the effect of greenhouse gases increase, in this particularly sensitive region, is also essentially unknown. The climate projections performed with state-of-the-art climate models in the frame of the Coupled Model Inter-comparison Program (CMIP) that serve as a basis for the IPCC reports (Intergouvernemental Panel for Climate Change), show a very large dispersion in terms of rainfall trends in that region. In fact, about the same number of models predict a drier or a wetter climate in Sahel.

The next IPCC-AR5 report will rely on simulations which are started now in the main climate centers around the world. Joint to the CMIP5 exercise, with global coupled ocean-atmosphere climate models, their will be a coordinated exercise for regional models (Cordex), and the main target of this exercise will be Africa. It is presumable that the dispersion of the coming simulations will be as large (or probably even larger due to the larger variety of models) than for the previous report.

The expectation for those simulations is huge for those who want to try to think to the possible consequences of those climate changes on exo-systems and societies. However, if an important effort is not done to assess for which reason some models predict more rainfall in the future, and other less, and to try to improve the physical content of the models, the frustration may be at the level of the expectations. One important question in that respect, is to understand the contribution of natural variability, global warming or other forcing to the recent decadal evolution of the west-african monsoon.

The AMMA project.

The international African Monsoon Multi-disciplinary Analysis (AMMA) project, originally developed from a french initiative, had for general objectives the improvement of our understanding of the west african monsoon and its variability, from diurnal scale to inter-anual. The project was motivated by the large variability of precipitations associated with the monsoon system, and by their consequences for the food security, water resources and health.

An enormous efforts was done in terms of observations, reinforcement of networks and dedicated intensive observing periods (SOPs) during summer 2006. This campaign resulted in some important improvements in our understanding of key processes in the monsoon climate system.

Evaluation and improvement of climate models, imbeded from the beginning in the AMMA project, gave rise to the AMMA-Model Intercomparison Program (AMMA-MIP). The AMMA-MIP exercise showed some ability of the atmospheric global and regional numerical climate models to represent the seasonal cycle of the rainfall over west-africa, but also the large dispersion of simulated rainfall distribution over the Sahel. One important issue was to show that the dispersion seems to be even greater in terms of fluxes (radiative, sensible and latent) at the surface, variables which were note measured in that region, before the campaign.

The IPCC schedule.

The new CMIP5 exercise is now on its way. The results of the new climate simulations have to be made available to the international community at the end of 2010. The scientific teams will then have a little bit more than one year to start analyze the simulations and submit papers, if they want to contribute to the IPCC AR5 report.

AMMA-MIP is a very appropriate framework to evaluate those new simulations in terms of the representation of the West-African climate, and to make a full exploitation of the hudge effort supported in particular by the AMMA-France and AMMA-EU programs, in terms of observations. In fact, under the pressure of the AMMA-MIP team, specific sites were selected (13 among 115 all around the world) for the documentation at high frequency of the climate models output, on the AMMA-transect. In particular, the constraints in terms of coupling at the surface and water budget

over the West-African continent is a real outcome from the campaign, which must be used in the future for model evaluation.

Teams and tools : a new maturity.

Also in terms of observations, a step has been made, both for satellites, with in particular the constellation of the Aqua-train, and for surface measurements, with the deployment of surface stations with eddy-flux and radiation measurements. 12 eddy flux towers were deployed on the AMMA transect during 2005 and 2006 instead of nothing. This gives for the first time direct constraints on the surface fluxes, a key variable to asses the realism of the representation of physical processes in the climate model.

The physical content of numerical climate models, which had been a little be abandoned in the past decades to concentrate on the building of complex coupled so-called Earth-System-Models, this physical content has been greatly improved recently. It is true especially for the LMDZ model which will be used in this project.

During the AMMA program, major steps have been made also in the understanding of the intra-seasonal variability of the monsoon system, and its link with global modes of the tropical variability.

Last important point : the AMMA program has been a unique occasion to put together communities which were not familiar to work together. We think in particular that for the ambitious objectives we want to address here, we need to have expertise on the tropical variability, atmosphere and coupled surface/atmosphere process and their observations, and numerical climate modeling.

General positioning of the project

In that context of the new CMIP exercise arriving just after the end of the major phase of the AMMA program, we propose a project that we hope could be a major contribution to the understanding of climate variations in west Africa. The general objectives will be :

• To make a real profit of the AMMA observations to assess the IPCC simulations, in particular in terms of coupling variable at the atmosphere/surface interface.

• Make a major step forward in the understanding of the coupled surface/atmosphere processes and there role in the climate variations in west Africa, at the various space and time scales, from intra-seasonal to decadal.

• Assess the role of those processes in the decadal variations of the seasonal distribution of rainfall over west-Africa, both in terms of natural variability and consequences of the global warming.

2. DESCRIPTION SCIENTIFIQUE ET TECHNIQUE / SCIENTIFIC AND TECHNICAL DESCRIPTION

2.1. ÉTAT DE L'ART / BACKGROUND, STATE OF THE ART

(2 pages maximum)

Présenter un état de l’art national et international dressant l’état des connaissances sur le sujet et décrivant le contexte et les enjeux scientifiques dans lequel se situe le projet. Faire apparaître d’éventuels résultats préliminaires.

Fig 2 : A model study of the decenal variation of the cumulated rainfall over the Sahel (Zeng et al., 1999).

Decadal climate variations in west-Africa

The Sahel, the transition region between the wet tropical climate of the coast of Gulf of Guinea and the Sahara desert, is the region of the planet which has undergone the largest modifications of its rainfall regime during the last decades (Trenberth et al. 2007) with huge consequences on the local eco-systems and societies. The precipitation showed very marked decadal variability, with a great negative trend between wet conditions in the 1950s and 1960s, to very dry ones in the 1970s and 1980s, followed by a partial recovery in the 1990s and 2000s (Lebel and Ali 2009). A number of studies have highlighted the instrumental role of Sea Surface Temperatures (SST) in driving such variability (Folland et al. 1986, Palmer 1986, Giannini et al. 2003). The world-wide warming trend of SST, associated to the global warming trend, has been related to the Sahel drying, highlighting the dominant role of the tropical Indian (Bader and Latif 2003, Giannini 2003, Lu and Delworth 2005) and tropical Pacific (Lu and Delworth 2005, Caminade and Terray 2009). Nevertheless, over the whole 20th century, the Sahel precipitation decadal changes cannot be solely explained by the global warming trend of SST. The partial recovery may be attributed to the interference of internal multidecadal variability in the Atlantic Ocean (the AMO, a SST pattern connected to the oceanic thermohaline circulation; Knight et al 2005) with the global warming signal: Atlantic SST strengthened the Sahel drying induced by warming of the oceans when in a phase that favored a southward location of the Intertropical Convergence Zone (ITCZ) in the 1970s and 1980s, but are now in a configuration favorable for Sahel rainfall, hence they are partially counteracting the drying trend associated with global warming (Ting et al 2009, Mohino et al. 2009).

However we know since the pioneer work of Charney (1975) that land-atmosphere interactions can play also a significant role on the West African monsoon decadal variability, even if it seems to act mainly as an amplification of the SST forcing signal (Zeng et al. 1999; Giannini et al. 2003). For instance the divergence of CMIP3 climate models in projections of future rainfall change in the Sahel (see below) cannot be attributed to the simulated spatial patterns of SST change (Biasuttti et al. 2008) and could be due to differences in the response of the land surface directly related to the local interactions of precipitation, evaporation and anthropogenic influence on radiative forcing at the surface (Giannini 2009). The GLACE project has demonstrated that the sub-Saharan region has a very high land-atmosphere sensitivity, whose amplitude is also highly variable depending on the climate models (Koster et al. 2004). The causes of such variations in coupling strength are linked to the ability of soil moisture to affect precipitation mainly through the control of evaporation, an evaporation rate that varies strongly and consistently with soil moisture leading to a higher coupling strength (Guo et al. 2006).

Another factor, the Saharan and Sahel dust, whose emissions are partly linked to the land conditions through the variations of the vegetation coverage (either from climatic or land-use changes), might also have an important role on the African monsoon decadal variability through its radiative impact (Yoshioka et al. 2007).

Hence, the complete explanation for the strong climate decadal variation of the Sahel is still an open question, and is at the heart of this proposal.

Teams and tools: a new maturity (smaller scales)

During the AMMA program, major steps have been made also in the understanding of the intra-seasonal variability of the African monsoon system, and its link with global modes of the tropical variability although a comprehensive view is still lacking (Janicot et al. 2010). Three main modes of

variability have been highlighted during the summer, a quasi-stationary mode over the Guinean area and a westward propagating mode of the Sahel at a quasi-biweekly scale, and a westward propagating mode at a 40-day scale linked to the MJO events over the Indian sector. They have a regional extension and represent an envelope modulating the activity of individual mesoscale convective systems. These modes appear to be controlled both by internal atmospheric dynamics and land-atmosphere and radiation-atmosphere interaction processes (Taylor 2008, Lavender et al. 2009). More investigation is needed addressing also the role of internal atmospheric processes like transient-mean flow interactions between the African easterly jet and the African easterly waves. These modes may also be linked with the extra-tropical atmospheric dynamics.

Previous work (Le Barbé et al. 2002) has shown that the rainfall regime difference at decadal scale over the period 1950-1990 has been characterized by a lower rainfall events occurrence during the drought period. This confirms that the mesoscale and the synoptic scale are main scales where the coupling processes can be addressed. AMMA has provided new knowledge about the land-atmosphere interactions, highlighting the impact of mesoscale gradients of soil moisture on mesoscale low-level circulations and convection initiation and propagation, and the complexity of soil moisture – convection feedback loops at the different stages of the convective systems life cycle (Taylor et al. 2007, Gaertner et al. 2009, Gantner and Kalthoff 2009, Taylor et al. 2009).

2.2. OBJECTIFS ET CARACTÈRE AMBITIEUX/NOVATEUR DU PROJET / RATIONALE HIGHLIGHTING THE ORIGINALITY AND NOVELTY OF THE PROPOSAL

(2 pages maximum)

Décrire les objectifs scientifiques/techniques du projet.

Présenter les avancées scientifiques attendues. Préciser l’originalité et le caractère ambitieux du projet.

Détailler les verrous scientifiques et techniques à lever par la réalisation du projet.

Décrire éventuellement le ou les produits finaux développés à l’issue du projet montrant le caractère innovant du projet.

Présenter les résultats escomptés en proposant si possible des critères de réussite et d’évaluation adaptés au type de projet, permettant d’évaluer les résultats en fin de projet.

Le cas échéant, démontrer l'articulation entre les disciplines scientifiques et le caractère interdisciplinaire du projet.

One of the objectives is to make the links between decadal climate variations of the African monsoon and atmospheric and coupled land surface/atmosphere processes, in order to better evaluate which processes are critical in the possible amplification of the SST forcings and to better understand the sources of the huge dispersion of the climate models scenarios in this region.

We must better determine the fingerprint of the decadal scale : how does it modulate the life cycle, the intensity and the frequency of the mesoscale systems, the intraseasonal modes of convection, the seasonal cycle of the monsoon ? Do the climate model reproduce similar features ? What has happened during the recent rainfall recovery respect to the preceding drought ?

Another issue is to determine the relative contribution of coupled ocean-atmosphere modes, internal atmospherie variability, and coupled processes at the surface to the decadal variations of the seasonal

distribution of rainfall over West Africa. Does the internal atmospheric variability belong to a large scale dynamics or is it mainly controled by local land-atmosphere processes ? What are the key processes responsible for the coupling between the monsoon system and surface ? What is the main time scales of the land memory effects ?

How evaporation and monsoon circulation (moisture convergence) contribute to rainfall depending on the intensity and life cycle of the rainfall events ? and at intraseasonal scale ?

Is it possible to constrain the simulated decadal variations due to both internal variability of the climate system and global warming trends with the available observations (supersites and satellites for short term processes, and long term obs for the link between short term and decadal scales) ?

Analyses of the series and hierarchy of climate simulations, including the forced and coupled simulations simulations performed in the CMIP frame work.

Run a series of specific simulations with iontermediate complexity versions of the LMDZ model to assess the relative contribution of pure internal atmospheric variability and coupled processes in the decadal varaitions of the climate system.

Make use of the super-site observations to asses the correlation between coupling variables at the surface (temperature, humidity, radiative fluxes, latent and sensible heat fluxes).

Evaluate the model in terms of those coupling variables, proposing diagnostics caracterizing the behaviour of the coupled surface/monsoon system. Improve the representation of coupling variables in the climate models.

Role of atmospheric and coupled atmosphere/surface processes in the variability of the monsoon system, at decadale time scale.

Evaluation, oriented toward coupled atmosphere/surface processes and

Scientific questions :

What is the relative contribution of coupled ocean-amtophere modes, internal atmsopherie variability, and coupled processes at the surface to the decadal variations of the seasonal distribution of rainfall over west africa ?

What are the key processes responsibe for the coupling between the monsoon system and surface ?

What are the surface feedback involved in those decadal variations.

Is it possible to constrain the simulated decadal variations due to both intenal variability of the climate system and global warming trends with the available observations (supersites and satellites for short term processes, and long term obs for the link between short term and decadal scales) ?

Practical objectives and work to be done :

Analyses of the series and hierarchy of climate simulations, including the forced and coupled simulations simulations performed in the CMIP frame work.

Run a series of specific simulations with iontermediate complexity versions of the LMDZ model to assess the relative contribution of pure internal atmospheric variability and coupled processes in the decadal varaitions of the climate system.

Make use of the super-site observations to asses the correlation between coupling variables at the surface (temperature, humidity, radiative fluxes, latent and sensible heat fluxes).

Evaluate the model in terms of those coupling variables, proposing diagnostics caracterizing the behaviour of the coupled surface/monsoon system.

Improve the representation of coupling variables in the climate models.

3. PROGRAMME SCIENTIFIQUE ET TECHNIQUE, ORGANISATION DU PROJET / SCIENTIFIC AND TECHNICAL PROGRAMME, PROJECT MANAGEMENT

3.1. PROGRAMME SCIENTIFIQUE ET STRUCTURATION DU PROJET / SCIENTIFIC PROGRAMME, SPECIFIC AIMS OF THE PROPOSAL

(4 pages maximum)

Présentez le programme scientifique, la méthodologie et la structuration du projet.

Justifiez la décomposition en tâches du programme de travail en cohérence avec les objectifs poursuivis.

Les tâches représentent les grandes phases du projet. Elles sont en nombre limité.

Présenter les liens entre les différentes tâches (si possible, utilisez un diagramme ou un organigramme technique).

Fig 3 : The AMMA/AMMA-MIP framework.The map shows the annual cumulated rainfall from GCP (mm) showing the stronger latitudinal than longitudinal variations as well as the location of the AMMA super-sites in Benin, Niger and Mali (from South to North) and the longitude band (10W-10E) retained to compare zonally averaged structure in the AMMA-Cross intercomparison.

Fig 5 : Location of the specific sites retained for high frequency output in a subset of the control simulations done with the CMIP atmospheric models.

3.2. COORDINATION DU PROJET / PROJECT MANAGEMENT

(2 pages maximum)

Préciser les aspects organisationnels du projet et les modalités de coordination (si possible individualisation d’une tâche coordination : cf. tâche 0 du document de soumission administratif).

Important question because one important goal is to put together scientists from different specialities (process study, surface, observations, climate physicist, climatolgists) around a common objective.

Role of coordinator : make sure that the tasks is connected to the others.One meeting each 6 month.

3.3. DESCRIPTION DES TRAVAUX PAR TÂCHE / DETAILED DESCRIPTION OF THE WORK ORGANISED BY TASKS

(idéalement 1 ou 2 pages par tâche)

Pour chacune d’entre elle, décrire : - son responsable et les partenaires impliqués (si possible, sous forme graphique),- ses objectifs,- le programme détaillé des travaux2,- la description des méthodes, des choix techniques et des solutions envisagés,- les risques et les solutions de repli envisagées, les indicateurs de succès associés aux objectifs

et les livrables,- les contributions des partenaires (le « qui fait quoi »).

3.3.1 TÂCHE 1 / TASK 1 EVALUATION OF CLIMATE MODELS AND CLIMATE CHANGE SIMULATIONS

This first task is dedicated to the evaluation of the climate model which will be involved in the next IPCC-AR5 report, through the CMIP5 and Cordex exercise.

2 types of simulations will be evaluated :

2 Les projets de recherche s’appuyant sur les données réunies, par exemple, dans le cadre de la constitution d’un corpus, d’un suivi de cohorte, d’une approche longitudinale, d’un panel, doivent expliciter précisément la nouveauté du recueil de données envisagé, la nouveauté des traitements ou des analyses proposées par rapport à ceux déjà engagés.

− The control simulations performed with coupled ocean-atmosphere models. It is presumable that, as for the previous CMIP3 exercise, the biases in the cumulated rainfall over Sahel will be quite large due to large scale biases in the sea-surface temperature.

− The control simulations performed with atmosphere-alone models forced by Sea-Surface-Temperature of the recent decades. This include climate versions of the CMIP simulations as well as Cordex simulations with WRF and LMDZ.

Validation tool and observations :

− The AMMA-MIP framework will be used. It is based on the evaluation on a few selected years (2000, 2003, 2005, and 2006) and focused on the documentation of the meridional/seasonal distribution of rainfall, meteorological variables, large scale dynamics, and fluxes.

− The models outputs will consists both in cross-section (latitude-altitude averaged on 10W-10E, AMMA-CROSS framework) and 2D horizontal maps (AMMA-MAPS) on a daily baisis and the specific high frequency outputs made along the transect in the frame of the CFMIP project.

− The use of super-site observations of the “interface variables” will be used.

− The recent satellite observations (in particular those of the aqua-train) will be preprocessed for validation.

The work will be divided into 5 sub-tasks :

T1A : evaluation of the mean seasonal cycle of rainfall, temperature and large scale dynamics in the coupled ocean-atmosphere simulation. Because the coupled simulations are not representative of a particular year, a mean-climatology will be build from the observations as an extension of the present AMMA-MIP framework.

T1B : evaluation of the atmosphere-alone simulations (CMIP and Cordex) using the current AMMA-MIP diagnostics on the CMIP5 and Cordex simulations. In practice, this requires to develop an automatic interface between the standards retained for the outputs of the CMIP simulations and the AMMA-CROSS and AMMA-MAP files required by AMMA-MIP.

T1C : Improvement of the AMMA-MIP observation dataset. In particular, better documentation of clouds and meridional/seasonal variations based on the observations of the aqua-train, and of water vapor based on recent reanalysis of the AMMA-campaing (using in particular GPS and AMMA radio-sound data).

T1D : definition of process oriented diagnostics taking into account the results of task 2, based on the used of “interface variable” observations. Define key diagnostics for the relative variations of the various variables for the wet Benin site and semi-arid Niger and Mali sites.

T1E : Apply new diagnostics to characterize the models in terms of the representation of the distribution of rainfall events, both at short term (link with convective “events”) and at intra-seasonal time scales (break, active phases).

3.3.2 TASK 2 : ANALYSE OF COUPLED ATMOSPHERE/SURFACE PROCESSES FROM THE “INTERFACE VARIABLES”

Responsible : Françoise Guichard

Teams involved : CNRM, LMD, CRC

Materials and methods.

Observations : In situ measurements (fluxes, n'co) + satelites (clouds, ratiation TOA).

Models : Control simulations of the CMIP models with forced Ssts. WRF and LMDZ Cordex simulations. Forced simulations with various configurations of LMDZ. Zoomed/nudged simulations of LMDZ for the years with available observations.

T2A : Characterize the successive phases of the seasonal cycle of the African monsoon in terms of observed meteorological variables and fluxes at the super-sites, and interpretation in terms of water vapor, clouds and dust. Link with TOA satellite observations.. Compare with the mean seasonal cycle in climate simulations.

T2B : Identify robust features in the “interface variables” like :: constancy of the LW down radiation, “thermostatage” par la pluie sur certains sites (?) or others to be identify. Use the simulations to explain those robust climatic features when they are present or identify model defficiencies.

T2C : Look at correlation between variables with time filtering, phase lag ... Both in the in-situ measurements and models. Identify characteristic behaviors. Contrast the wet Benin and semi-arid Niger and Mali sites. Comparison with results from atmospheric climate simulations. Once again, use the model for interpretation or identify model weaknesses.

T2D : Make composite of those correlations as a function of the phase of the seasonal cycle, or/and phases of the modes dominating the tropical variability.

T2E : Characterize the seasonal and intra-seasonal variations of radiative fluxes

T2F : Document the inter-annual variability for the few years for which in-situ observations are available, and compare the coupled processes at this inter-annual time scale with that at shorter period.

3.3.3 TASK 3 : ANALYSE OF DECADAL CLIMATE VARIATIONS OF THE SEASONAL CYCLE OF RAINFALL IN SAHEL.

Responsible : Serge JanicotTeam involved : Locean, LMD, CRC, CNRM

Materials and methods :Observations : long term series from CRU, MeteoSat TOA radiation, TRMM data, atmospheric reanalyses.

Models : CMIP3 and CMIP4 simulations with forced by sea surface temperature and coupled ocean-atmosphere model, both for present climate and simulations with evolving greenhouse gases

concentrations. Secular simulations with intermediate complexity simulations with the LMDZ model : forced by a composite seasonal cycle of SST of a wet or dry decade ; and/or coupled to surface humidity or forced by prescribed humidity.

Work:

T3A : Document the decadal variations of the seasonal cycle of rainfall, temperature and humidity over Sahel from CRU observations and in situ measurements when available. Document the decadal variations of TOA radiation from MSG and of rainfall products from TRMM. Link with observed decadal variations of the seasonal cycle of Sahelian rainfall in CMIP simulations. Document the contrasted behaviour of correlations between coupling variables at the various supersite locations in the simulations, contrasting the wet energy limited regime and dry water limited regime.

T3B : Analyse the climate simulation in various configurations (forced, coupled, with interactive humidity or even vegetation or not) to assess the contribution of the coupled atmosphere/ocean modes, internal atmospheric variability, and coupled atmosphere/surface processes to the decadal variability of the rainfall in Sahel. In particular, compare the decadal variations in the CMIP control run with that in the CMIP climate change simulations to separate the contribution from global warming. Try to relate the (probably) contrasted (see Giannini 2009) behaviour of the models to the caracteristics of the representation of convection and rainfall variability and/or surface processes in the models.

T3C : Develop a composite analysis based on the rainfall events distribution and their life cycle in the various model configurations in order to assess at this scale the relative contributions of the local land surface processes and of the regional monsoon circulation interactions linked to regional scale low-level horizontal moist static energy gradients. Develop a similar approach at the intraseasonal time scale. Role of the cloud radiative forcing ?

T3D : Analyse the secular simulations performed with various configurations ... long-term simulations forced by a fixed seasonal SST cycle have been performed with LMDZ and showed that a strong part of the variability is not coupled to the ocean. Why ? Redo this experiment with the new physics of LMDZ to see to what extent it is sensitive to the physical content of the model and with fine resolution regular grids. Does this internal atmospheric variability belong to a large scale dynamics or is it mainly controled by local land-atmosphere processes ?

T3E : Identify the key processes at the various scales and see if there is a way to validate or improve the models at those scales (inclure dans l'une des autres sous-tâches ?).

3.3.4 TASK 4 : REPRESENTATION OF INTERFACE VARIABLES AND EXPLORATION OF THE ROLE OF COUPLED ATMOSPHERE/SURFACE PROCESSES IN NUMERICAL MODELS

Responsible : Jean-Yves GrandpeixTeams involved : LMD, CNRM

Objectives: (i) Assess the role of the various components of the LMDZ4 model which are supposed to play a key role in the simulation of the West Africa climate at scales ranging from 100km to a few 100 km and from a day

to a year: PBL/Convection/Clouds parametrization package, aerosol parametrization, land-surface model; (ii) Improve these components when possible and necessary; (iii) Perform specific simulations used in tasks 2 and 3.

Key questions:

(i) What are the consequences of the new physics package of LMDZ (PBL scheme, deep convection scheme, density current scheme)on the simulation of the WA climate? Especially, what are the consequences of thechange of the diurnal cycle of moist convection?

(ii) What are the important features of the land surface model?

(iii) What are the relevant interface variables in order to couple properly the atmosphere and land surface processes? Especially, is the sub-grid heterogeneity of surface moisture a relevant interface variable?

T4A: Use of the new physics of LMDZ and better representation of the life cycle (in particular diurnal cycle) of convective events (even if the parameterized convection is still far from real MCS) to asses the impact on the representation of raditive fluxes (change of the phasing between clouds and insolations) and latent/sensible fluxes (changes in the phasing of rainfall with warmest temperature).

Test of the new boundary layer scheme and its impact on the representation of boundary layer shallow cumulus and their impact on surface fluxes.

T4B: Mineral aerosols. Test and improvement of the representation of interactive dust in LMDZ

and link with surface fluxes.

T4C: 1D simulations (this work is part of Nicolas Rochetin thesis)

(i) Assessment of the PBL/Convection/clouds sensitivity to surface and atmospheric large scale conditions. Use of radiative-convective equilibrium simulations in order to compare LMDZ4 SCM results with a CRM. This work is a continuation a work performed during the AMMA european program (WP1.3.3, Collaboration with Paolina Cerlini, University of Perugia).

(ii) Parametrization of the effect of sub-grid surface moisture heterogeneity on the triggering of deep convection. The role of this parametrization will be assessed by comparing LMDZ4 SCM results with CRM

results in radiative-convective equilibrium simulations.

(iii) Representation and analysis of the feedback loop [soil moisture heterogeneity] -> [deep convection] -> [deep convective rain] -> [soil moisture heterogeneity]. In order to represent this process, a stochastic model of sub-grid soil moisture will be designed, with the convective rain as a source term. The PDF of soil moisture and rain rate will be assessed from CRM simulations.

T4D: 2D simulations

Use 2D latitude-altitude version of MesoNH to study the coupling between

surface and atmosphere at various time scales.

T4E : Sensitivity experiments with the LMDZ/Orchidee 3D General Circulation Model.One important tool of the project is the realisattion of long (secular) climate simulations with various configurations of the LMDZ/Orchidee model. LMDZ is the atmospheric component of the climate model developed at LMD while Orchidee is the scheme for continental surface.In the project, we will rely for the analyses of the coupled ocean-atmosphere contribution to the varability on the CMIP5 simulations (which will include some simulations with the IPSL model as well). The purpose here is to explore more specifically the coupling between the surface and atmosphere and the role of this coupling for the decenal variability. For this, we will performed simulations forced either by the mean seasonal cycle for a wet decade (1956-1965) or that of a dry decade (1975-1984). This contrasted sets of sea-surtface-temperature was shown recently to force a decadal signal in the rainfall over Sahel which present interesting similarities with the observed signal. When replacing the interactive computation of surface humidity by orchidee, by a prescribed seasonal cycle of humidity, the interdecadal variability was significantly reduced. The idea is to rerun similar experiments with different physical content of the atmospehric and surface models, and with intermediate complexity configurations. In particular, the simulations will be done with the “old” and “new” LMDZ physical packages. Also, the simulations will be done with a hierarchy of configuration for the surface. Prescribed humidity, coupled humidity with a 2 layer or new 11-layer soil model ; use of prescribed seasonal cycle of the Leaf Area Index (LAI) or interactive computation ; use of interactive vegetation. Each simulation will last 200 years and will be duplicate for the dry and wet years.

3.4. CALENDRIER DES TÂCHES, LIVRABLES ET JALONS / PLANNING OF TASKS, DELIVERABLES AND MILESTONES

(2 pages maximum)

Présenter sous forme graphique un échéancier des différentes tâches et leurs dépendances (par exemple, utiliser un diagramme de Gantt).

Présenter un tableau synthétique de l'ensemble des livrables du projet (numéro de tâche, date, intitulé, responsable).

Préciser de façon synthétique les jalons scientifiques et/ou techniques, les points bloquants ou aléas qui risquent de remettre en cause l'aboutissement du projet ainsi que les réunions de projet prévues.

Schedule of the simulationsAvailable from the beginning :

CMIP3 (used for IPCC AR4 report). Secular simulations with intermediate configurations of LMDZ with a zoom grid and with our without coupling with the surface.

Available at the end of 2010.

CMIP simiulations with LMDZ (coupled, AMIP, ...) with 2 versions of the physical package.

CORDEX simulations with WRF and LMDZ.

Available at spring 2011

CMIP simulations, together with forced models.

4. STRATÉGIE DE VALORISATION DES RÉSULTATS ET MODE DE PROTECTION ET D’EXPLOITATION DES RÉSULTATS / DATA MANAGEMENT, DATA SHARING, INTELLECTUAL PROPERTY AND RESULTS EXPLOITATION

(1 à 2 pages)

Présenter les stratégies de valorisation des résultats :- la communication scientifique;- la communication auprès du grand public, le cas échéant;- la valorisation des résultats attendus;- les retombées scientifiques et techniques, éventuellement les retombées industrielles,

économiques …- la place du projet dans la stratégie industrielle des entreprises partenaires du projet- autres retombées (normalisation, information des pouvoirs publics, ...)- pour les bases de données, indiquer les modes de stockage et de maintenance ainsi que les

communautés bénéficiaires

Présenter les grandes lignes des modes de protection et d’exploitationes résultats.

Pour les projets partenariaux organismes de recherche/entreprises, les partenaires devront conclure, sous l’égide du coordinateur du projet, un accord de consortium dans un délai de un an si le projet est retenu pour financement.

Pour les projets académiques, l’accord de consortium n’est pas obligatoire mais fortement conseillé.

Promote the AMMA observations as a frame-work for CMIP model evaluation.Promote the AMMA-MIP framework.Promote in particular the supersite observations.

5. ORGANISATION DU PARTENARIAT / CONSORTIUM ORGANISATION AND DESCRIPTION

5.1. DESCRIPTION, ADÉQUATION ET COMPLÉMENTARITÉ DES PARTENAIRES / RELEVANCE AND COMPLEMENTARITY OF THE PARTNERS WITHIN THE CONSORTIUM

(maximum une demi page par partenaire)

Décrire brièvement chaque partenaire et fournir ici les éléments permettant d’apprécier la qualification des partenaires dans le projet (le « pourquoi qui fait quoi »). Il peut s’agir de réalisations passées, d’indicateurs (publications, brevets), de l’intérêt du partenaire pour le projet… (il ne s’agit pas de fournir ici le C.V. du responsable scientifique de chaque partenaire).

Fournir en annexe 7.2 une présentation plus détaillée des partenaires, de leur savoir- faire et de leurs apports et attentes dans le projet.

Montrer la complémentarité et la valeur ajoutée des coopérations entre les différents partenaires. L’interdisciplinarité et l’ouverture à diverses collaborations seront à justifier en accord avec les orientations du projet. (une page maximum)

5.2. QUALIFICATION DU COORDINATEUR DU PROJET / QUALIFICATION OF THE PROJECT COORDINATOR

(une demi page maximum)

Fournir les éléments permettant de juger la capacité du coordinateur à coordonner le projet.

5.3. QUALIFICATION, RÔLE ET IMPLICATION DES PARTICIPANTS / CONTRIBUTION AND QUALIFICATION OD EACH PROJECT PARTICPANT

Pour chaque partenaire, remplir le tableau ci-dessous qui précisera la qualification, les activités principales et les compétences propres de chaque participant :

Partenaire Nom Prénom Emploi actuel

Discipline Personne.mois

Rôle/Responsabilité dans le projet

4 lignes max

Exemple LATIFI Fatima Professeur Caractérisation des facteurs de transcription recombinants en système in vitro …

Coordinateur/responsable

Autres membres

Pour chacune des personnes dont l’implication dans le projet est supérieure à 25% de son temps sur la totalité du projet, une biographie d’une page maximum sera placée en annexe 7.2 du présent document qui comportera :

- Nom, prénom, âge, cursus, situation actuelle

- Autres expériences professionnelles

- Liste des cinq publications (ou brevets) les plus significatives des cinq dernières années, nombre de publications dans les revues internationales ou actes de congrès à comité de lecture.

- Prix, distinctions

Si besoin, pour chacune des personnes, leur implication dans d'autres projets (Contrats publics et privés effectués ou en cours sur les trois dernières années) sera présentée selon le modèle fourni en annexe 7.3. On précisera l'implication dans des projets européens ou dans d’autres types de projets nationaux ou internationaux. Expliciter l’articulation entre les travaux proposés et les travaux antérieurs ou déjà en cours.

6. JUSTIFICATION SCIENTIFIQUE DES MOYENS DEMANDÉS / SCIENTIFIC JUSTIFICATION OF REQUESTED BUDGET

On présentera ici pour chaque partenaire, la justification scientifique et technique des moyens demandés dans le document de soumission administratif. Ces moyens sont synthétisés à l’échelle du projet dans la fiche «Tableaux récapitulatifs » dans ce document de soumission administratif.

Chaque partenaire justifiera les moyens qu’il demande en distinguant les différents postes de dépenses selon le canevas suivant :.

6.1. PARTENAIRE 1 / PARTNER 1 : XXX

1. Équipement / Equipment

Préciser la nature des équipements* et justifier le choix des équipements

Si nécessaire, préciser la part de financement demandé sur le projet et si les achats envisagés doivent être complétés par d’autres sources de financement. Si tel est le cas, indiquer le montant et l’origine de ces financements complémentaires.

*Un devis sera demandé si le projet est retenu pour financement.

2. Personnel / Staff

Le personnel non permanent (thèses, post- doctorants,CDD..) financé sur le projet devra être justifié.

Fournir les profils des postes à pourvoir pour les personnels à recruter (une demi page maximum par type de poste)

Pour les thèses (ne concerne ni la biologie-santé, ni les sciences humaines et sociales), préciser si des demandes de bourse de thèse sont prévues ou en cours, en préciser la nature et la part de financement imputable au projet.

3. Prestation de service externe / Subcontracting

Préciser :

- la nature des prestations

- le type de prestataire.

4. Missions / Missions

Préciser :

- les missions liées aux travaux d’acquisition sur le terrain (campagnes de mesures…)

- les missions relevant de colloques, congrès…

5. Dépenses justifiées sur une procédure de facturation interne / Internal expenses

Préciser la nature des prestations

6. Autres dépenses de fonctionnement / Other expenses

Toute dépense significative relevant de ce poste devra être justifiée.

6.2. PARTENAIRE 2 / PARTNER 2 : XXX

…

7. ANNEXES

7.1. RÉFÉRENCES BIBLIOGRAPHIQUES / REFERENCES

Inclure la liste des références bibliographiques utilisées dans ce document et les références bibliographiques des partenaires ayant trait au projet.

Bader J, Latif M (2003) The impact of decadal scale Indian ocean SST anomalies on Sahelian rainfall and the North Atlantic Oscillation. Geophys Res Lett 30: 2169. Doi:10.1029/2003GL018426

Biasutti, M., I. M. Held, A. H. Sobel, and A. Giannini, 2008: SST forcings and Sahel rainfall variability in simulations of 20th and 21st centuries. J. Climate, 21, 3471–3486.

Caminade C, Terray L (2009) Twentieth century Sahel rainfall variability as simulated by the ARPEGE AGCM, and future changes. Clim Dyn. DOI:10,1007/s00382-009-0545-4

Charney, J. G., 1975: Dynamics of deserts and drought in the Sahel. Q. J. Roy. Meteor. Soc., 101, 193–202.

Folland CK, Palmer TN, Parker DE (1986) Sahel rainfall and worldwide sea temperatures, 1901-85. Nature 320:602-607. Doi:10.1038/320602a0

Gaertner, M.A., M. Dominguez and M. Garvert (2009) A modelling case-study of soil moisture – atmosphere coupling. Quart. J. Roy. Met. Soc., doi:10.1002/qj.541.

Gantner L. and N. Kalthoff (2009) Sensitivity of a modelled life cycle of a mesoscale convective system to soil conditions over West Africa. Quart. J. Roy. Met. Soc., doi:10.1002/qj.425.

Giannini A, Saravannan R, Chang P (2003) Oceanic Forcing of Sahel Rainfall on Interannual to Interdecadal Time Scales. Science 302:1027-1030

Giannini, A. (2009) mechanisms of climate change in the semi-arid African Sahel: the local view. J. Climate, Early online release, doi:10.1175/2009JCLI3223.1.

Guo, Z. et al. (2006) GLACE: The Global Land-Atmosphere Coupling Experiment. Part II: Analysis. J. Hydromet., 7, 611-625.

Janicot, S. et al, 2010; Seasonal and intra-seasonal variability of the West African monsoon. Accepted Atmos. Sci. Lett., Special issue ASL on AMMA.

Koster, R.D., P A. Dirmeyer, Z Guo, G Bonan, E Chan, P Cox, C. T. Gordon, S Kanae, E Kowalczyk, D Lawrence, P Liu, C-H Lu, S Malyshev, B McAvaney, K Mitchell, D Mocko, T Oki, K Oleson, A Pitman, Y. C. Sud, C M. Taylor, D Verseghy, R Vasic, Y Xue, T Yamada, 2004: Regions of Strong Coupling Between Soil Moisture and Precipitation, Science, 305, 5687, 1138–1140, doi: 10.1126/science.1100217.

Knight JR, Allan RJ, Folland CK, Vellinga M, Mann ME (2005) A signature of persistent natural thermohaline circulation cycles in observed climate. Geophys Res Lett 32. DOI:10.1029/2005GL024233

Lavender, S.L., C. M. Taylor and A.J. Matthews, 2009. Coupled land-atmosphere intraseasonal variability of the West African monsoon in a GCM. In revision J. Climate.

Le Barbé, L., T. Lebel and D. Tapsoba (2002) rainfall variability in West Africa during the years 1950-90. J. Climate, 15, 187-202.

Lebel, T. and A. Ali (2009) Recent trends in the central and western Sahel rainfall regime (1990-2007). J. hydrology, 375, 52-64.

Lu J, Delworth TL (2005) Oceanic forcing of the late 20th century Sahel drougth. Geophys Res Lett 32. DOI:10.1029/2005GL023316

Mohino, E., S. Janicot and J. Bader, 2010: The impact of the long-term global warming and the Atlantic Multi-dedadal Oscillation on the West African monsoon. Submitted Climate Dyn.

Palmer TN (1986) Influence of the Atlantic, Pacific, and Indian Oceans on Sahel rainfall. Nature 322:251–253

Taylor, C.M., 2008. Intraseasonal land-atmosphere coupling in the West African monsoon. J. Climate, 21, 6636-6648.

Taylor, C.M., D.J. Parker and P.P. Harris (2007) An observational case study of mesoscale atmospheric circulations induced by soil moisture. Geophys. Res. Lett., 34, L15801, doi:10.1029/2007GL030572.

Taylor, C.M., P.P. Harris and D.J. Parker (2009) Impact of soil moiture on the development of a Sahelian mesoscale convective system: A case-study from the AMMA Special Observing Period. Quart. J. Roy. Met. Soc., doi:10.1002/qj.465.

Ting M, Kushnir Y, Seager R, Li Cuihua (2009) Forced and internal 20th century SST trends in the North Atlantic. J Clim 22:1469-1481

Trenberth KE, Jones PD, Ambenje P, Bojariu R, Easterling D, Klein Tank A, Parker D, Rahimzadeh F, Renwick JA, Rusticucci M, Soden B, Zhai P (2007) Observations: Surface and Atmospheric Climate Change. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL (eds.) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, N.Y., USA

Yoshioka M, Mahowald NM (2007) Impact of desert dust radiative forcing on Sahel precipitation: Relative importance of dust compared to sea surface temperature variations, vegetation changes and greenhous gas warming. J Clim 20:1445-1467. DOI:10.1175/JCLI4056.1

Zeng N, Neelin JD, Lau KM, Tucker CJ (1999) Enhancement of interdecadal climate variability in the Sahel by vegetation interaction. Science 286:1537-1540

7.2. BIOGRAPHIES / CV, RESUME

(une page maximum par personne)

Cf. § 5.3.

7.3. IMPLICATION DES PERSONNES DANS D’AUTRES CONTRATS / INVOLVEMENT OF PROJECT PARTICIPANTS TO OTHER GRANTS, CONTRACTS, ETC …

(un tableau par partenaire)

Cf. § 5.3.

Mentionner ici les projets en cours d’évaluation soit au sein de programmes de l’ANR, soit auprès d’organismes, de fondations, à l’Union Européenne, etc. que ce soit comme coordinateur ou comme partenaire. Pour chacun, donner le nom de l’appel à projets, le titre du projet et le nom du coordinateur.

Part.

Nom de la personne

participant au projet

Personne. mois

Intitulé de l’appel à projets

Source de financement

Montant attribué

Titre du projet

Nom du coordinateur

Date début &

Date fin

N°

N°