Lagrangian single-column modeling of Arctic airmass transformation

As warm and moist airmasses are advected into the Arctic, a sequence of turbulent, microphysical and radiative processes is initiated which transfers heat and moisture from the airmass into the Arctic environment, eventually transforming both. Despite the importance of airmass transformation for the evolution of the Arctic climate, it is still relatively poorly understood. In our study, we take on this complex issue from a Lagrangian perspective, using warm-air intrusions captured by different Arctic campaigns (ACSE, MOSAiC, HALO-(AC)³ and ARTofMELT) and the Atmosphere-Ocean Single Column Model (AOSCM). We use trajectory analysis to assess under what conditions and to what extent this Lagrangian AOSCM framework is suitable to study the Arctic airmass transformation. Finally, we use it to simulate the changes in heat-moisture content and vertical structure of the airmass at different stages of the transformation and identify the physical processes that drive them. Comparison with observations, reanalysis and operational forecast data shows that the Lagrangian AOSCM can be used for future model analysis and diagnostics development.