A5085293514- Climate variability and models
- Meteorological Phenomena and Simulations
- Tropical and Extratropical Cyclones Research
- Oceanographic and Atmospheric Processes
- Climate change impacts on agriculture
- Agriculture and Rural Development Research
- Hydrology and Drought Analysis
- Geophysics and Gravity Measurements
- French Urban and Social Studies
- Precipitation Measurement and Analysis
- Atmospheric aerosols and clouds
- African Botany and Ecology Studies
- Climate Change and Health Impacts
- Marine and coastal ecosystems
- Plant Water Relations and Carbon Dynamics
- Atmospheric chemistry and aerosols
- Aeolian processes and effects
- Coastal and Marine Management
- Plant Ecology and Soil Science
- Bacterial Infections and Vaccines
- Rangeland Management and Livestock Ecology
- Ocean Waves and Remote Sensing
- Atmospheric and Environmental Gas Dynamics
- Global Energy and Sustainability Research
- Geology and Paleoclimatology Research
Sorbonne Université
2013-2024
Institut de Recherche pour le Développement
2014-2024
Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques
2014-2024
Centre National de la Recherche Scientifique
2014-2024
Muséum national d'Histoire naturelle
2023
Structure et Instabilité des Génomes
2023
Institut de Recherche pour le Développement
2021-2022
Institut Pierre-Simon Laplace
2004-2021
Columbia University
2017
Université de Versailles Saint-Quentin-en-Yvelines
2016
The arrival of the summer monsoon over West Africa has been documented by using daily gridded rainfall data and NCEP–NCAR reanalyses during period 1968–90, OLR 1979–90. Two steps have characterized through a composite approach: preonset onset monsoon. stage corresponds to in intertropical front (ITF) at 15°N, that is, confluence line between moist southwesterly winds dry northeasterly Harmattan, bringing sufficient moisture for isolated convective systems develop Sudano–Sahelian zone while...
Abstract A 47‐year record (1951–1997) of gridded data covering Africa south the Sahara was used to document spatial and seasonal patterns correlation between precipitation sea‐surface temperatures (SST) in key tropical areas, as depicted by NIÑO3, South Atlantic North indices. El Niño–Southern Oscillation (ENSO) is confirmed playing a dominant part northeastern, eastern southern Africa. However, its impact also found over Sahel during northern summer, other parts Gulf Guinea region outside...
The West African heat low (WAHL), a region of high surface temperatures and pressures, is key element the monsoon system. In this study, we propose method to detect WAHL in order monitor its climatological seasonal displacement over Africa during period 1979–2001, using European Centre for Medium-range Weather Forecast (ECMWF) ERA-40 reanalyses. low-level atmospheric thickness (LLAT), variable defined as difference geopotential heights at 700 925 hPa, used dilatation these levels generated...
Abstract Stratospheric aerosols from large tropical explosive volcanic eruptions backscatter shortwave radiation and reduce the global mean surface temperature. Observations suggest that they also favour an El Niño within 2 years following eruption. Modelling studies have, however, so far reached no consensus on either sign or physical mechanism of response to volcanism. Here we show tends peak during year in simulations Fifth Coupled Model Intercomparison Project (CMIP5). Targeted climate...
The onset of the monsoon system over West Africa is linked to northward migration Inter‐Tropical Convergence Zone (ITCZ) during northern spring and summer. By using daily gridded rainfall data NCEP/NCAR wind reanalyses period 1968–1990, we show that this characterised by an abrupt latitudinal shift ITCZ in late June from a quasi‐stationary location at 5N May–June another 10N July–August. A composite analysis based on dates shows associated with occurrence westward‐travelling depression...
Background Every year West African countries within the Sahelo-Sudanian band are afflicted with major meningococcal meningitis (MCM) disease outbreaks, which affect up to 200,000 people, mainly young children, in one of world's poorest regions. The timing epidemic year, starts February and ends late May, spatial distribution cases throughout “Meningitis Belt” strongly indicate a close linkage between life cycle causative agent MCM climate variability. However, mechanisms responsible for...
Correlations between summer Sahel rainfall and Southern Oscillation Index has increased during the last thirty years. At high frequency time scale (periods lower than 8 years), an intertropical Atlantic zonal divergent circulation anomaly is forced by difference of sea surface temperature (SST) anomalies eastern equatorial parts Pacific Atlantic. This connection worked well most El Nino/Southern (ENSO) events occurring after 1970; positive/negative SST in Pacific/Atlantic led to deficits...
Intraseasonal variability in the West African monsoon is documented by using daily gridded datasets of rainfall and convection, reanalyzed atmospheric fields, over period 1968–90. Rainfall convection Africa are significantly modulated at two intraseasonal timescales, 10–25 25–60 day, leading to variations more than 30% seasonal signal. A composite analysis based on dates maximum (minimum) a regional index wet (dry) sequences shows that these last, average, 9 days belong main quasiperiodic...
Abstract. The AMMA (African Monsoon Multidisciplinary Analysis) program is dedicated to providing a better understanding of the West African monsoon and its influence on physical, chemical biological environment regionally globally, as well relating variability this system issues health, water resources, food security demography for nations. Within framework, an intensive field campaign took place during summer 2006 document specific processes weather systems at various key stages season....
Abstract We review the studies carried out during African Monsoon Multidisciplinary Analysis (AMMA)‐EU on changes of interannual sea surface temperature (SST)–West monsoon (WAM) covariability at multidecadal timescales, together with influence global warming (GW). The results obtained in AMMA‐EU suggest importance background state, modulated by natural and anthropogenic variability, appearance different modes. lack reliability current coupled models giving a realistic assessment for WAM...
Sea surface temperature (SST) anomalies in the tropical Atlantic have been associated with precipitation West Africa that form a dipole pattern centers over Sahel and Gulf of Guinea. Whilst this was clear before 1970's, almost disappeared after date, as anti‐correlation between rainfall Guinea dropped abruptly. Simultaneously, anti‐correlations Pacific SSTs strengthened. It has posited these changes 1970's developed started to co‐vary global tropics. In co‐variability, enhanced summer...
Abstract. The objective of this paper is to present a new dataset bias-corrected CMIP5 global climate model (GCM) daily data over Africa. This was obtained using the cumulative distribution function transform (CDF-t) method, method that has been applied several regions and contexts but never Here CDF-t period 1950–2099 combining Historical runs change scenarios for six variables: precipitation, mean near-surface air temperature, maximum minimum surface downwelling shortwave radiation, wind...
General circulation models (GCM) are increasingly capable of making relevant predictions seasonal and long-term climate variability, thus improving prospects predicting impact on crop yields. This is particularly important for semi-arid West Africa where variability drought threaten food security. Translating GCM outputs into attainable yields difficult because grid boxes larger scale than the processes governing yield, involving partitioning rain among runoff, evaporation, transpiration,...
Four West African rainfall anomaly types are defined in relation to the northern summer departure signs Sahel and Guinean region order investigate statistical links between interannual variability of sea surface temperature (SST) through period 1950–90. Composite analysis depicts setup four different mean SST fields. Drought over all Africa is associated with growth positive anomalies eastern Pacific Indian Ocean, negative Atlantic Gulf Guinea. In contrast, drought limited corresponds mostly...
Abstract 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 15 days and one around 40 days. These regional can strongly influence precipitation convective activity. They mainly controlled by atmospheric dynamics land–surface interactions. also modulate the very specific phase African summer monsoon onset. A better knowledge mechanisms controlling this...
Abstract This study aims at assessing the consistency between different precipitable water vapour (PWV) datasets over Africa (between 35°N and 10°S). region is characterized by large spatial temporal variability of humidity but also scarcity its operational observing network, limiting our knowledge hydrological cycle. We intercompare data from techniques such as ground‐based Global Positioning System (GPS), radiosondes, AERONET sun photometers SSM/I, well reanalyses European Centre for...