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Ongoing PhD projects

Atmospheric deposition of nitrate on subalpine meadows at the Lautaret Pass

Ilann Bourgeois (2015-2017)

Increasing rates of atmospheric nitrate deposition in mountainous basins, now well documented by alpine ice cores and emission inventories of the Western countries, involve critical changes in nitrogen (N) availability with consequences on biodiversity (plants, microbes), soils, and water nutrients (C, N) status leading to vulnerability of critical ecosystem services (i.e., provision of clean (...)

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The role of greenhouse gases in past climate variations: an approach based on precise chronologies of deep polar drillings

Jai Chowdhry Beeman (2016-2019)

Ice cores drilled in Antarctica and Greenland allow us to reconstruct key climatic variables during the past hundreds of thousands of years. These variables include temperature, precipitation, atmospheric impurities and trace gases, in particular greenhouse gases: CO2, CH4 and N2O. To accurately determine the relationships between these variables in the climate system, we must construct (...)

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Physique de la fermeture des pores dans le névé polaire, implications pour la compréhension des rétroactions passées entre cycle du carbone et climat

Kévin Fourteau (2016-2019)

Dans un contexte de changement climatique forcé par les activités anthropiques, progresser dans notre compréhension des mécanismes de rétroaction entre variabilité climatique et cycle du carbone demeure un enjeu majeur pour mieux simuler les évolutions futures du climat. Les archives glaciaires peuvent y contribuer en renseignant les variations passées des températures et de la composition (...)

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Recent variability of humidity toward East Antarctica by the analysis of water stable isotopes and chimical measurements

Sentia Goursaud (2015-2018)

The IPCC reported in the AR5 that Antarctica is the highest reservoir of water. However, the characterisation and the comprehension of the mechanisms which are responsible for the recent variability of the climate in Antarctica remain unclear (especially because of the spatial and temporal low cover of the meteorological recordings), remaining its future uncertain. This reservoir is supplied (...)

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Evolution of atmospheric 13CO2 during rapid changes of CO2 in the past : a marker of climate-carbon coupling mechanisms

Jinhwa Shin (2015-2018)

Model simulations of the future climate now rely on the close coupling between climate and the carbon cycle. This coupling could reduce the natural sink of carbon dioxide (CO2) from anthropogenic origin, or even transform into CO2 sources the natural carbon reservoirs under the effect of global warming. The coupling takes place both in the ocean compartment (biological pump intensity, (...)

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Ice flow modelling to locate an old-ice coring site

Olivier Passalacqua (2014-2017)

The ice core community, in the frame of the IPICS (International Partnership In Ice Core Science), has decided to drill an ice core as old as 1.5 million years in Antarctica, covering a period during which it is known, thanks to marine oce cores, that the climate main periodicity has changed, from 40,000 years to 100,000 years (Lisiecki and Raymo, (...)

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Regional variability of polar snow densification during large climatic transitions

Camille Bréant (2014-2017)

The phasing between increases in temperature and greenhouse gas concentrations during large climatic variations in the past is classically estimated using analyses in polar ice cores. It is still badly constrained. Solving this problem requires to better understand the mechanical process of snow to ice metamorphism over the top 100 m of the ice sheet (i.e. the (...)

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