This manuscript reports on new 2-year long time series of atmospheric water vapor and precipitation isotopic composition measurements at Dumont d’Urville station, in Adelie Land. The authors provide diurnal and seasonal variations of meteorological parameters and isotopic compositions of atmospheric water vapor and precipitation, determine the relationships of delta 18O and temperature (humidity). Then, they evaluate the simulations from ECHAM6-wiso and quantify contributions of continental and oceanic grid cells to fit the observations. They also simulated delta 18O record in S1C1 firn core using temperature and precipitation from ERA5 or ECHAM6-wiso. They conclude that ECHAM6-wiso allows to better explain the delta 18O record in firn core than with the only influence of temperature.

Overall, the narrative of this manuscript is easy to follow, and the necessity of this study is well elaborated. The data analysis provides enough evidences for the conclusion. I would recommend the editor accept the manuscript after minor revision. I have following general comments:

• The abstract is a bit cursory without concision, and lacks some important conclusions. I would suggest the authors rewrite it.

• The description of the isotopic calibration is lacking detail and uncertainties. The plots of drift correction should be provided in SI. Delta 18O-humidity calibration data from SDM are missed in Fig. S2.

• The influence of synoptic events does not address very well. Some descriptions are not clear at seasonal or events scales. For instance, what is the difference of such events between winter and summer, and what is the reason for those distinct influences in L150-155? How could get the conclusion in L315-317?

• The evaluation of d-excess from ECHAM6-wiso is missing in section 3.2. The d-excess variability is well established from observations, but does not show any related analysis to combine with simulations. Why?

• I can not get the point clearly in L243-246. It seems controversial with the conclusion.

• Increase all font sizes in figures and figures are too small to see details.

• It is hard to compare the vapor data and precipitation data when they are plotted on separate panels with distinct axis scales in Fig. S9.