Dominant Role of Arctic Dust With High Ice Nucleating Ability in the Arctic Lower Troposphere

Recent observations show that dust emitted within the Arctic (Arctic dust) has a remarkably high ice nucleating ability, especially between -20 degrees C and -5 degrees C, but its impacts on the number concentrations of ice nucleating particles (INPs) and radiative balance in the Arctic are not well understood. Here we incorporate an observation-based ice-nucleation parameterization indicating the high ice nucleating ability of Arctic dust into a global aerosol-climate model. A simulation using this parameterization better reproduces INP observations in the Arctic and estimates >100 times higher dust INP number concentrations with similar to 100% contribution from Arctic dust in the Arctic lower troposphere (>60 degrees N and >700 hPa) during summer and fall (June-November) than a simulation applying a standard ice-nucleation parameterization suitable for desert dust to Arctic dust. Our results demonstrate the importance of considering an ice-nucleation parameterization suitable for Arctic dust when simulating INPs and their effects on aerosol-cloud interactions in the Arctic.