Research

Overview

My research focuses on the atmospheric water cycle in Antarctica, with a particular emphasis on water isotopes. During my PhD, I used the LMDZ6iso global atmospheric model to simulate isotope dynamics; from November 2026, I will work with the regional model CRYOWRF at SLF.

In Antarctica, the study of water isotopes in surface snow, precipitation, and vapour is conducted with a dual objective: gaining a deeper understanding of isotopic signals archived in ice cores, and deciphering the contributions of different atmospheric processes in driving the water cycle, including boundary layer processes.

Atmospheric general circulation models (AGCMs) with water isotopes provide a crucial tool for simulating fractionation and transport processes. They allow us to investigate isotopic signatures across different timescales, from meteorological events to seasonal and interannual variations, as well as past climate reconstructions within a physically coherent framework.

Upcoming · SLF, from November 2026

Airborne snow metamorphism and polar snow isotopes

From November 2026, I will join the Snow Physics group of the WSL Institute for Snow and Avalanche Research SLF in Davos for a two-year postdoc with Benjamin Walter, within a project funded by the Swiss National Science Foundation (SNSF).

The project investigates the newly discovered process of airborne snow metamorphism (ASM): the transformation of snow particles during wind-driven transport, and its impact on the physical properties and isotopic composition of polar snow. My work will consist in:

• developing new model equations for the evolution of snow microstructure and isotope signals during wind-driven snow transport, parameterized from laboratory and Antarctic field data;
• implementing them in the coupled atmosphere–snow model CRYOWRF;
• quantifying the impact of ASM on the isotopic composition, energy and mass balance of polar regions.

This work directly extends my PhD results, which suggested that airborne sublimation of blowing snow could leave a different isotopic signature than surface sublimation (see Study 3 below).

Current · LSCE, 2026

Atmospheric rivers, snow–vapour interactions and ice-core archives

Since January 2026, as a postdoctoral researcher at LSCE with Mathieu Casado, I study snow–vapour interactions during the March 2022 Antarctic atmospheric river, and whether such extreme events are archived in ice. To do so, I combine the LMDZ model, a proxy-system model and high-resolution East Antarctic ice cores.

PhD work · 2022–2025

Water vapour isotopes in Antarctica

My PhD, supervised by Cécile Agosta at LSCE, was carried out within the AWACA ERC Synergy project (Atmospheric WAter Cycle over Antarctica).

Study 1 - Antarctic water stable isotopes in the global atmospheric model LMDZ6: from climatology to boundary layer processes

My first study focuses on evaluating the LMDZ6iso global atmospheric model by comparison with surface snow isotopes across Antarctica, as well as daily precipitation and continuous water vapour isotopes at two East Antarctic stations: Dumont d’Urville (coastal) and Concordia (inland). This evaluation examines spatial, seasonal, and diurnal isotopic variations in the model.

Next, I analysed the contributions of individual processes to boundary layer water vapour isotopes, aiming to identify the key drivers of clear-sky isotopic daily cycles and to explain discrepancies between model simulations and observations.

• At Concordia, daily isotope variations are mainly driven by surface sublimation.
• At Dumont d’Urville, they are influenced by both surface sublimation and advection by the katabatic flow.

These results suggest that further improvements in LMDZ6iso should prioritise better representation of isotopic exchanges during sublimation and condensation under low temperatures.

Study 2 - Water vapour isotope anomalies during an atmospheric river event at Dome C, East Antarctica

My second study focuses on analysing the isotopic anomaly in water vapour induced by the passage of an atmospheric river over Concordia in December 2018. The isotopic composition of water vapour observed during this event can be explained by two key processes:

• the isotopic signature of long-range water transport;
• local moisture uptake during the event.

Using the LMDZ6iso simulation previously evaluated, we show that surface sublimation is the primary driver of the positive isotopic anomaly in vapour, contributing 60% of the total signal. This sublimation effect is significantly increased during the event compared to typical diurnal cycles. The remaining 40% of the anomaly is attributed to large-scale moisture advection associated with the atmospheric river.

These results highlight that the isotopic signal recorded in water vapour during atmospheric river events reflects a combination of long-range moisture advection and interactions between the boundary layer and the snowpack, reinforcing the importance of local surface processes in shaping Antarctic isotope variability.

Study 3 - Improving isotopic surface fluxes over snow in LMDZ6iso: evaluation at Dome C, East Antarctica (submitted)

Building on the first two studies, my third study targets the representation of isotopic surface fluxes over snow in LMDZ6iso. In most isotope-enabled models, sublimation over iced surfaces is treated as non-fractionating, and surface condensation is parametrized like cloud condensation.

Combining continuous meteorological and water vapour isotope measurements at Concordia with LMDZ6iso, we:

• implement fractionation during sublimation, which depletes the sublimation flux relative to the snow and drives the vapour toward isotopic equilibrium with the snow;
• adopt for surface condensation the same formulation as for water vapour, making the isotopic flux depend on the near-surface humidity and isotopic gradients.

Evaluated over summertime diurnal cycles in December 2018 and January 2024, these developments significantly improve the simulated amplitude of the vapour isotope diurnal cycle. The updated model, however, does not capture the strong anomaly observed during the atmospheric river event. We hypothesise that blowing snow sublimating entirely in the atmosphere produced vapour with an isotopic composition close to that of the snow, suggesting that airborne sublimation could leave a different isotopic signature than surface sublimation.

Projects & collaborations

• Antarctica InSync (since 2026): co-lead of the water stable isotope working group, with Sonja Wahl (University of Bern) and Amy Macfarlane (LSCE), coordinating a pan-Antarctic isotope observation network.
• AWACA – Atmospheric WAter Cycle over Antarctica (ERC Synergy Grant, 2022–2026): LMDZ modelling component, evaluation against Antarctic isotope observations and development of a new isotopic surface scheme.
• WisoMIP – Water Isotope Model Intercomparison Project (since 2025): LMDZ contributor, reference 1979–2024 simulation.

Fieldwork