A5020794086- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Isotope Analysis in Ecology
- Astro and Planetary Science
- Geological formations and processes
- Spacecraft and Cryogenic Technologies
- Pleistocene-Era Hominins and Archaeology
- Groundwater and Isotope Geochemistry
- Offshore Engineering and Technologies
- Geophysics and Gravity Measurements
- Astronomical Observations and Instrumentation
- Hydrocarbon exploration and reservoir analysis
- Geological and Geophysical Studies
- Planetary Science and Exploration
- Geomagnetism and Paleomagnetism Studies
- Marine and environmental studies
- Geological Modeling and Analysis
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Climate variability and models
- Atmospheric and Environmental Gas Dynamics
- Satellite Image Processing and Photogrammetry
- Inertial Sensor and Navigation
- Nuclear Physics and Applications
- Pacific and Southeast Asian Studies
Environnements et Paléoenvironnements Océaniques et Continentaux
2014-2024
Université de Bordeaux
2013-2024
Centre National de la Recherche Scientifique
2013-2024
Institut Polytechnique de Bordeaux
2023-2024
Cardiff University
2022
International Ocean Discovery Program
2017
Ifremer
2015-2016
Vrije Universiteit Amsterdam
2013-2015
Université de Bretagne Occidentale
2015
University of Amsterdam
2014
The relationship between initial
Heat and salt transfer from the Indian Ocean to Atlantic (Agulhas leakage) has an important effect on global thermohaline circulation climate. The lack of long record prevents elucidation its role climate changes throughout Quaternary. Here, we present a 1,350-ka accumulation rate planktic foraminiferal species Globorotalia menardii. We demonstrate that, according previous assumptions, presence reseeding this fauna in subtropical southeast was driven by interocean exchange south Africa....
The rapidity and synchrony of the African Humid Period (AHP) termination at around 5.5 ka are debated, it is unclear what caused a rapid hydroclimate response. Here we analysed hydrogen isotopic composition sedimentary leaf-waxes (δDwax) from Gulf Guinea, proxy for regional precipitation in Cameroon central Sahel-Sahara. Our record indicates high during AHP followed by decrease 5.8-4.8 ka. similarity with δDwax northern East Africa suggests large-scale atmospheric mechanism. We show that...
Prior to ~1 million years ago (Ma), variations in global ice volume were dominated by changes obliquity; however, the role of precession remains unresolved. Using a record North Atlantic rafting spanning past 1.7 years, we find that onset within given glacial cycle (reflecting sheet expansion) consistently occurred during times decreasing obliquity whereas mass wasting (ablation) events tied minima precession. Furthermore, our results suggest ubiquitous association between precession-driven...
Abstract. The Agulhas Current transport of heat and salt from the Indian Ocean into South Atlantic around Africa (Agulhas leakage), can affect meridional overturning circulation (AMOC) and, thus, influence global climate. However, efforts to elucidate forcing mechanisms connecting leakage with upstream dynamics current have been hampered by a lack climate records extracted area where originates. We determine 800-kyr sea surface temperature (SST) salinity (SSS) "precursor" region show that...
Abstract. Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate climate system at edge tropics between Indian and Atlantic Oceans. However, records covering a full glacial cycle have only been published from eastern Atlantic. We present pollen record marine core MD96-2048 retrieved by Marion Dufresne Ocean ∼120 km south Limpopo River mouth. The sedimentation site is slow continuous. upper 6 m (spanning past 342 Ka) analysed for spores millennial resolution....
The Earth experienced dramatic climate changes during the past million years, including a long-term gradual cooling from Pliocene (5.3-2.6 years ago; Ma) to Pleistocene (2.6-0.011 and an abrupt transition 41-kyr 100-kyr glacial-interglacial cycles at ca. 1.2-0.8 Ma (i.e., Mid-Pleistocene transition). Investigating mechanisms that triggered these climatic responses requires transient simulations which can be used quantify sensitivity of Earth’s different external internal forcings....
The hydrological cycle plays a crucial role in the Earth’s climate and has direct impact on human populations. Despite advances, IPCC AR6 report highlights persistent uncertainties concerning future projections of potential changes cycle, particular for low latitudes monsoonal systems. This is because numerical models exhibit significant spread their projections.Traditionally, to estimate value variable, distribution from an ensemble examined. However, this uncertainty very high...
Internal variations of climate can significantly influence global warming trends, especially at the continental scale, and could contribute to recent abnormal observed over Europe. Model-based studies highlight that centennial variability North Atlantic strongly affect this sector. However, a lack high-resolution paleoclimate data does not allow proper evaluation real existence such mode nor its amplitude. Here, we compile series annual proxy-based reconstructions Europe from diverse sources...
Abstract The Indian‐Atlantic water exchange south of Africa (Agulhas leakage) is a key component the global ocean circulation. No quantitative estimation paleo‐Agulhas leakage exists. We quantify variability in interocean over past 640,000 years, using planktic foraminiferal assemblage data from two marine sediment records to define an Agulhas efficiency index. confirm validity our new approach with numerical model that realistically simulates modern changes. Our results suggest that, during...
Abstract. Very little is known about the impact of atmospheric carbon dioxide pressure (pCO2) on shaping biomes. The development pCO2 throughout Brunhes Chron may be considered a natural experiment to elucidate relationships between vegetation and pCO2. While glacial periods show low very values (∼220 ∼190 ppmv, respectively), levels interglacial vary from intermediate relatively high (∼250 more than 270 respectively). To study influence Pleistocene SE African vegetation, we used pollen...
Abstract. We use the fully coupled atmosphere–ocean three-dimensional model of intermediate complexity iLOVECLIM to simulate climate and oxygen stable isotopic signal during Last Glacial Maximum (LGM, 21 000 years). By using a that is able explicitly sensor (δ18O), results can be directly compared with data from climatic archives in different realms. Our indicate reproduces well main feature LGM atmospheric oceanic components. The annual mean δ18O precipitation shows more depleted values...
Abstract. The monsoon is one of the most important climatic phenomena: it promotes inter-hemispheric exchange energy and affects economical prosperity several countries exposed to its seasonal seesaw. Previous studies in both Indian Asian systems have generally suggested a dominant northern hemispheric (NH) control on summer dynamics at scale suborbital–millennial changes, while forcing/response monsoons orbital remains matter debate. Here, six marine sediment cores distributed across whole...
Abstract. The oxygen-18 to oxygen-16 ratio recorded in fossil planktonic foraminifer shells has been used for over 50 years many geoscience applications. However, different species generally yield distinct signals, as a consequence of their specific living habitats the water column and along year. This complexity is usually not taken into account model–data integration studies. To overcome this shortcoming, we developed Foraminifers As Modeled Entities (FAME) module. module predicts presence...
Species assemblage composition of marine microfossils offers the possibility to investigate ecological and climatological change on time scales inaccessible using conventional observations. Planktonic foraminifera - calcareous zooplankton have an excellent fossil record are used extensively in palaeoecology palaeoceanography. During Last Glacial Maximum (LGM; 19,000 23,000 years ago), climate was a radically different state. This period is therefore key target biodiversity under conditions...
Abstract. The H218O stable isotope was previously introduced in the three coupled components of earth system model iLOVECLIM: atmosphere, ocean and vegetation. results a long (5000 yr) pre-industrial equilibrium simulation are presented evaluated against measurement abundance present-day water for atmospheric oceanic components. For it is found that reproduces observed spatial distribution relationships to climate variables with some merit, though limitations following our approach...
Abstract. Oxygen stable isotopes (δ18O) are among the most useful tools in palaeoclimatology/palaeoceanography. Simulation of oxygen allows testing how past variability these water can be interpreted. By modelling proxy directly model, results also compared with data. Water have been implemented global three-dimensional model intermediate complexity iLOVECLIM, allowing fully coupled atmosphere–ocean simulations. In this study, we present validation for present-day climate against database...