The climate signal stored in stable water isotope records retrieved from polar ice cores contains information on different temporal and spatial scales. The isotopic composition of precipitated snow is an integrated proxy for the climate along the water parcel trajectory initiated by the evaporative conditions in the moisture source regions and influenced by every phase-change process along the water cycle pathway. Isotope records can be used to retrieve information on climate variability not only at the precipitation site, but also to gain information about the evaporation source regions. However, latest research has shown that post-depositional processes affecting the snow after deposition impact the signal effectively archived in the ice core water isotope records. To quantify these post-depositional effects using snow models special attention should be given to the second order parameters d-excess and O-excess which are sensitive to non-equilibrium processes. Here we present findings on the influence of the surface humidity fluxes for the ice core isotope signal on different timescales based on the SNOWISO snowpack and humidity exchange model with a focus on d-excess. We further discuss the model’s limitations and outline the necessary model development steps to quantify the effects of other post-depositional processes such as blowing and drifting snow and temperature-gradient driven sub surface vapor fluxes. This contribution is the initiation of the SnowDOGS (Snow D-excess OriGin Study) project which aims at improving our understanding of the transfer function between climate and ice core signal by incorporating post-depositional processes in an isotope-enabled snowpack model and validating it with existing water isotope records. We focus on presenting the status-quo on quantifying the post-depositional impact for the ice core isotope record and provide a platform for ideas exchange on how to best include O-excess in future studies.