Diagnosing moisture sources, transport and transformation in the Arctic withwater vapor isotopes in atmospheric modeling

The Arctic has been rapidly moistening over the last forty years, influencing energy fluxes and precipitation. While local changes in
air temperature and sea ice cover partly explain this trend, the role of changing moisture transport to the Arctic is less clear.
Understanding how moisture transport affects Arctic amplification is crucial, as most moisture in the Arctic comes from lower latitudes.
Enhanced warming in the Arctic strengthens meridional transport due to changes in Rossby waves, but current global climate
models struggle to capture these shifts accurately.

The presentation will show results from case studies of moisture transport into the Arctic, analyzing the changing structure of
water vapor isotopes in response to varying moisture transport patterns and phase transition along these transport pathways.
Initial simulations with the isotope-enhanced ICON-ART atmosphere model reveal limitations in its ability to accurately capture
isotopic variations on a global scale. Therefore, the model first needs to be improved and validated for global simulations.
Once these improvements are achieved, case studies are performed to assess phase transition processes in detail and
explore their response to recent warming.