Presentation
The ADELISE project aims to monitor the isotopic composition of water in water vapour, precipitation, blown snow and surface snow at the coastal and very windy Dumont d’Urville site. The deployment of a parallel system of surface isotope measurements at the Dôme C-Concordia Antarctic station, as part of the NIVO project, will enable us to estimate the isotope transfer function between the coast and the East Antarctic Plateau, and better interpret the isotope profile of the Dôme C deep core.
At these two stations, complementary measurements (meteorological, LIDAR, RADAR, aerosols) will enable us to interpret our measurements in greater detail.
Projets IPEV
Participants : LSCE, IGE
Estimating the current surface mass balance in Antarctica is fraught with considerable uncertainty. On the one hand, the amount of precipitation is difficult to estimate due to the influence of re-deposition by the wind, this phenomenon being particularly important in coastal regions due to strong katabatic winds. On the other hand, it is very difficult to estimate the impact of exchanges with the atmosphere (sublimation/condensation) due to the poorly understood dynamics of the boundary layer (presence of blown snow, supersaturation, impact of turbulence…). However, in the current context of climate change, it is essential to know the evolution of this mass balance in relation to climate variations over the recent period. The small number of observation stations on the Antarctic continent makes this work difficult.
The measurement of water isotopes of snow or short ice cores in Antarctica is currently the best tool for reconstructing climate variability in the absence of instrumental measurements. Indeed, due to the depletion of heavy isotopes in water masses during distillation from low to high latitudes, it is possible to link variations in temperature to variations in isotopic composition. However, the isotopic composition of snow is sensitive to many other effects during snow formation and deposition (kinetic fractionation effects, re-evaporation) and after deposition (diffusion, sublimation and frost deposition). While these effects complicate the direct interpretation of water isotopes in terms of past temperature variations, they also provide additional information on deposition conditions and water fluxes at the surface of ice caps.
Publications:
Bréant et al. (EPSL, 2019) : Coastal water vapor isotopic composition driven by katabatic wind variability in summer at Dumont d’Urville, coastal East Antarctica
Leroy-Dos Santos et al. (AMT, 2021) : A dedicated robust instrument for water vapor generation at low humidity for use with a laser water isotope analyzer in cold and dry polar regions. Leroy-Dos Santos et al. (TC, 2024) : From atmospheric water isotopes measurement to firn core interpretation in Adélie Land: a case study for isotope-enabled atmospheric models in Antarctica