The large Antarctic ice sheet is strongly connected to the Earth climate through the atmospheric circulation and water cycle. My research aims to better understand and model the processes involved in this water cycle, with two main areas of application: (i) improving reconstructions based on the isotopic signal of annually resolved firn cores and (ii) improving climate projections for the Antarctic ice sheet, in particular its contribution to sea level.

Understanding the climatic drivers of the water isotope signal measured in high-resolution firn cores requires a modelling chain comprising large-scale atmospheric water transport, air-snow exchanges and in-snow post-deposition processes. We recently leveraged newly deployed isotopic records in surface snow and water vapour in Antarctica to evaluate the isotope-enabled global atmospheric model LMDZiso. Then we used process decomposition to understand the origin of vapour isotopic variability in the model. Ongoing work aims at improving isotopic processes in snow and during air-snow exchanges. This is a fundamental step towards the use of water isotopes to constrain physical processes. It will also allow going to paleoclimate data assimilation with reduced uncertainties in the modelling chain.

Modelling the future of the Antarctic climate, including its surface mass balance, requires representing correctly both the large-scale circulation and the polar-specific processes at play. I designed specific metrics to evaluate the large-scale circulation of CMIP models in polar regions. I also developed diagnostics for evaluating the snow accumulation over the ice sheet, which I used to analyse and improve the estimation of the Antarctic surface mass balance. Then we focused on the improvement of polar processes in atmospheric models related to snow and boundary layer (albedo, densification, liquid water content, turbulence). Finally, we developed momentum budget decomposition to quantify the drivers of Antarctic surface winds.

I am pursuing the improvement of polar physics in the atmospheric model of IPSL, ICOLMDZiso, aiming at an integrated framework of the ocean-to-snow water cycle including water isotopes and coupling with ice sheet models.

Everyone is welcome.

Lieu
Amphithéâtre Claude Bloch
Bât 772 – SPhT, https://maps.app.goo.gl/YqtzUHmcKH2pKKuC7)
Site CEA de l’Orme des Merisiers, 91190 Gif-sur-Yvette

Visio
https://cnrs.zoom.us/j/96056797581?pwd=qavv7GONN9Yj38Uke6uid1bgDO7Pax.1

• Nerilie ABRAM, Rapportrice, Professeure à l’Australian National University (Australie)
• Marie DUMONT, Rapportrice, Directrice de Recherche au Centre National de Recherches Météorologiques (CNRM, Grenoble)
• Gaël DURAND, Rapporteur, Directeur de Recherche à l’Institut des Géosciences de l’Environnement (IGE, Grenoble)
• Amaëlle LANDAIS, Examinatrice, Directrice de Recherche au Laboratoire des Sciences du Climat et de l’Environnement (LSCE)
• Hans Christian STEEN LARSEN, Examinateur, Associate Professor à l’University of Bergen (Norvège)
• Martin WERNER, Examinateur, Professeur à l’Alfred Wegener Institute (Allemagne)