Atmospheric River Induced Arctic Sea Ice Variability: Investigations in Low- and High-Resolution Climate Models

Present literature has established that Arctic Atmospheric River (AR) events play an important role in influencing Arctic sea ice loss and variability. More specifically, thermodynamic and dynamic processes, such as poleward moisture advection, drive changes in the local atmospheric radiative budget that subsequently warms the environment. Given that the Arctic exhibits higher sensitivity to variations in the climate compared to the rest of the world, there is an increased need to quantify changes in AR characteristics and strength with time. This study uses the output from the Historical simulations of the 5th phase of the Coupled Model Intercomparison Project (CMIP5) and 6th phase of the Coupled Model Intercomparison Project (CMIP6) to explore how differences in model version and resolution impact uncertainties in modeled AR statistics and Arctic sea ice response. Explicitly, we utilized model output from the International Laboratory for High-Resolution Earth System Prediction (iHESP) High-Resolution Model Intercomparison Project (HighResMIP), the Community Earth System Model Large Ensemble (LENS) [ten-member mean], and the Community Earth System Model version 2 Large Ensemble (LENS2) [ten-member mean], to investigate these uncertainties. Comparisons between LENS and LENS2 were made to quantify uncertainties between model versions, while comparisons between iHESP HighResMIP and LENS were made to quantify uncertainties between model resolutions. Results from this study show that model resolution plays a key role in our ability to resolve regional variability in AR-induced sea ice loss. As a result, we conclude that increased model resolution plays a fundamental role in our ability to accurately represent changes within the cryospheric system. By comparing these differences to those received via the exploration of model version quantification, we develop a more holistic representation of the roles ARs have in modulating the Arctic climate system.