Validity of the isotopic thermometer in central Antarctica: limited impactof glacial precipitation seasonality and moisture origin.

The classical interpretation of water stable isotopes (deuterium or oxygen Is) retrieved from ice cores into past local temperature relies on the use of the spatial isotope/temperature slope as a surrogate of the temporal slo pe. Whereas this assumption has been challenged by independent methods in c entral Greenland, it is still considered as valid in central Antarctica. We use an atmospheric General Circulation Model (GCM) to study two parameters highlighted by previous studies as being among the most important with res pect to this assumption. We show that in the GCM, between present-day and L ast Glacial Maximum, the change in precipitation seasonality and the coolin g of the moisture sources have limited and opposite effects on the isotopic record of the Antarctic local temperature. This conclusion strengthens the validity of the classical interpretation of isotope records in central Ant arctica.