| Summary: | Reducing uncertainty in the future climate projections depends strongly on our understanding of past and present climate. Water stable isotope composition of snow or ice are among the main paleoclimatic records in Antarctica . One way to interpret these isotopic signals is to use isotope-enabled atmospheric general circulation models (AGCMs).Here, we focus on the evaluation of two of them, LMDZ6-iso and ECHAM6-wiso, using a unique set of isotopic observations in water vapor, in precipitation, and in surface snow samples. These data were obtained at four sites representing different areas of the Antarctic region: a station on the sub-Antarctic island of Amsterdam, two stations in the coastal region - Dumont d'Urville in East Antarctica and Vernadsky in the Antarctic Peninsula, and one station on the East Antarctic plateau - Concordia. To identify the origins of discrepancies between models and observations, we divide our observational dataset into a range of synoptic conditions that samples various influences of large-scale meteorological processes and local boundary layer processes on the surface water isotopes.We then use model outputs to further describe the processes controlling the observed isotopic signal in water vapor and precipitation.In addition to helping interpret the isotopic signal from ice cores, this analysis also aims at understanding and improving the physical parameterizations related to moisture transport, precipitation formation and boundary layer processes in atmospheric models used to make future projections.
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