Impact of accumulation rate on firn core water isotopic records from a same region of Adelie Land with high katabatic winds

Whereas water isotopic records from polar deep ice cores can be interpreted at first order in terms of site temperature, the isotopic signature recorded in shallow cores from Adelie Land (coastal East Antarctica) is less straightforward to decipher (Goursaud et al. 2017, 2019; Leroy-Dos Santos, PhD 2021, 2023). The origin of moist air masses bringing precipitation, the influence of blowing snow, redistribution or sublimation strongly imprint the isotopic signal recorded in firn cores of this region where katabatic winds blow hard. Nonetheless these firn archives are our best way to reconstruct the recent past climatic trend and variability in this area where meteorological monitoring is very sparse and recent. In this study we compare the water isotopic profiles from firn cores (20 to 70m deep) drilled only a few kilometers apart, in the so-called “D47” area, about 150km inland from Dumont d’Urville at an altitude of 1500m. This site is characterized by very strong katabatic winds and mean accumulation rates can locally vary by several tens of percent. We can thus investigate the effect of very locally different deposition conditions on the isotopic records while the recorded regional climate is the same.