0000000000263522
AUTHOR
Romain Marteau
showing 10 related works from this author
The onset of the rainy season and farmers’ sowing strategy for pearl millet cultivation in Southwest Niger
2011
A multi-year (2004-2009) field survey of on-farm sowing practices in 10 villages located in south-west Niger close to Niamey, is analysed to investigate the relationships (i) between rainfall and the sowing date of pearl millet and the risk of sowing failure, (ii) between sowing and meteorological/agro-climatic onset dates, (iii) between sowing/onset dates, and simulated and observed yield/biomass at the end of the season. Even if some villages sow without any synchronous or anterior rainfall, most parcels (73% out of the 1551 available cases) are sown during and just after a 2-day wet spell receiving at least 10 mm. In fact, there is a strong correlation (r = 0.82-0.95 depending on onset d…
Recent changes in precipitation, ITCZ convection and northern tropical circulation over North Africa (1979-2007)
2011
This article focuses on some recent changes observed in the Tropics with special emphasis on the African monsoon region using high-resolution gridded precipitation from the Climatic Research Unit (period 1979–2002), outgoing longwave radiation at the top of the atmosphere from the National Oceanic and Atmospheric Administration and atmospheric reanalyses from the Climate Prediction Center (NCEP-DOE2, period 1979–2007). The results show a rainfall increase in North Africa since the mid-90s with significant northward migrations of rainfall amounts, i.e. + 1.5° for the 400 mm July to September isohyets, whereas deep convection has significantly increased and shifted northward. The subsidence b…
Monsoon Multidisciplinary Analysis (AMMA) : an integrated project for understanding of the West African climate system and its human dimension
2011
International audience; The intraseasonal time scale is critical in West Africa where resources are highly rainfall dependent. Three main modes of variability have been identified, two with a mean periodicity of 15 days and one with a mean periodicity around 40 days. These modes have a regional scale and can strongly influence precipitation and convective activity. They are mainly controlled by atmospheric dynamics and land-surface interactions. They can also modulate the very specific phase of the African summer monsoon onset. A better knowledge of the mechanisms controlling this scale is necessary to improve its predictability.
Spatial coherence of monsoon onset over Western and Central Sahel (1950-2000)
2009
Abstract The spatial coherence of boreal monsoon onset over the western and central Sahel (Senegal, Mali, Burkina Faso) is studied through the analysis of daily rainfall data for 103 stations from 1950 to 2000. Onset date is defined using a local agronomic definition, that is, the first wet day (>1 mm) of 1 or 2 consecutive days receiving at least 20 mm without a 7-day dry spell receiving less than 5 mm in the following 20 days. Changing either the length or the amplitude of the initial wet spell, or both, or the length of the following dry spell modifies the long-term mean of local-scale onset date but has only a weak impact either on its interannual variability or its spatial coher…
Utilisation d'ensembles de simulations climatiques sur Modèles de Circulation Générale de l'Atmosphère: concepts, méthodes et applications à la clima…
2003
International audience
Spatial coherence of agronomic boreal monsoon onset over Western and Central Sahel (1950-2000).
2007
Poster Presentation
Vulnerability and adaptation of agriculture to climate variability and change in the Sahel: results from the AMMA program
2012
Date de semis du mil et variabilité intrasaisonnière des précipitations au Niger
2012
Le rôle du déterminisme pluviométrique, et plus spécifiquement du démarrage de la saison des pluies, sur les pratiques agricoles a été évalué à partir de l'exemple de la culture du mil dans la région de Niamey parce que celle-ci y occupe une place prépondérante. Cette analyse, à l'interface du climat et des sociétés, a été réalisée à partir d'enquêtes agronomiques conduites en milieu paysan sur l'observatoire AMMA-CATCH Niger sur un carré de100 km x 100 km au NE de Niamey entre 2004 et 2007. Par ailleurs, le démarrage de la saison des pluies repose sur des considérations subjectives qui dépendent fortement de l'utilisateur. Ainsi, ce dernier est de nature équivoque dans ces régions semi-ari…
Évolution des températures observées en Bourgogne (1961-2011)
2014
International audience; Depuis un demi-siècle environ, l’augmentation des concentrations atmosphériques en gaz à effet de serre a entraîné une élévation de température qui peut être analysée selon des échelles emboîtées, allant de la planète aux territoires. Dans cette étude, les mesures effectuées sur le réseau de stations Météo-France sont mobilisées pour analyser la température en Bourgogne sur la période 1961-2011. Le réchauffement observé a des caractéristiques très proches des moyennes françaises. Il est plus fort que sur la moyenne planétaire. Il est marqué par une rupture nette délimitant deux périodes bien différentes : 1961-1987 et 1988-2011. Une interpolation par régression krige…