Sea Salt Aerosols from Blowing Snow: Contributions to Radiative Forcing

Abstract. The Arctic and Antarctic regions experience significant climate impacts from aerosol-cloud-radiation interactions, yet the role of sea salt aerosols (SSA) emitted through blowing snow remains poorly quantified. This study implements a parameterization of the SSA production of blowing snow in both the TM5 global chemical transport model and the EC-Earth3 global climate model, for AMIP-type as well as transient (SSP3-7.0 for 2015–2051) experiments, assessing the contributions of the blowing snow process to aerosol mass, number, cloud condensation nuclei (CCN) and radiative forcing in both polar regions. Model results are evaluated against observations from the MOSAiC campaign and coastal stations (Villum, Zeppelin, Alert). EC-Earth3 Simulations show that blowing snow substantially increases SSA concentrations during polar winter and spring, especially in the Antarctic where enhancements can exceed 100 % increase in particle numbers, leading to improved agreement with surface and in situ observations. Regionally, TM5 reveals an increase in accumulation mode aerosol and CCN. The resulting surface radiative forcing is globally negative due to increased scattering of shortwave radiation, while enhanced CCN increases longwave cloud effects in the polar lower troposphere. Overall, this work demonstrates that including blowing snow SSA emissions is essential for realistically representing polar aerosol burdens, seasonal cycles, and climate feedbacks in global models.