Better constrain mass balance evolution and recent climate and water cycle evolution in Adelie Land and Amsterdam Island using water isotopes

Water isotopic composition in Antarctica is an essential tool to reconstruct the climate and water cycle organization of the past from ice and snow core analyses. It is also largely used in Antarctica and lower latitude region to document moisture transport associated with synoptic events. In particular, isotopes of water vapor and precipitation are very useful to document the dominant moisture source and moisture trajectory, a property which is being used in the study of atmospheric rivers. Within the previous ADELISE project, we have successfully deployed water vapor isotopic analyzers at the Dumont d’Urville (DDU) station (since December 2018) and at Amsterdam Island (since December 2019). The instruments are providing continuous measurements since their installation and show a clear isotopic signature associated with moist synoptic events in both sites. This first set of isotopic measurements and interpretation provides a solid background for several projects recently funded (ERC CoG ICORDA associated with IPEV project 1250; ERC Syn AWACA – 2021 – 2027; ANR ARCA – 2021 – 2024) with the aim to further study the evolution of atmospheric surface mass balance and atmospheric water cycle in Antarctica combining water isotopic measurements in the water vapor and snowflakes with regional atmospheric modeling, remote sensing and meteorology measurements.
In this second phase of the ADELISE project, we want to maintain the current measurements at Amsterdam Island for the study of water cycle in the southern hemisphere and strengthen the observations at DDU by adding a new analyzer for low humidity level as well as a system able to measure continuously the isotopic composition of individual snowflakes. We will also make strong links with complementary data obtained continuously at Amsterdam Island (ozone, gaseous elemental mercury), remote sensing instruments to be installed at DDU, atmospheric modelling with isotopes and use back trajectory tools recently developed to make the link between the different isotopic analyzers installed at La Réunion (already in place), Amsterdam Island (already in place), DDU (already in place), Concordia (already in place), on the ICORDA-KATABATIC transect (to happen in 2022-2023) and in the 3 autonomous containers to be installed along the route of the logistical raid between the coast and the plateau within the ERC AWACA.