Characterization of blowing snow aerosol events in the central Arctic

<p>Sea salt aerosols play a critical role in aerosol-radiation and aerosol-cloud interactions. Salty blowing snow has been hypothesized as an important source of sea salt aerosol in polar regions. The snow over sea ice can become salty by upward brine migration or deposition of sea spray produced from leads or transported from the ice edge. Wind-driven resuspension and sublimation of the snow is hypothesized to leave salty aerosol particles behind. Our understanding of aerosol emissions from blowing snow is based mainly on modeling studies, and direct observations to validate this process are sparse. The year-long Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition, with its integrated measurements and sampling of frequent winter storms, is well suited to enhance our understanding of coupled Arctic system processes. Here, we focus on the impact of blowing snow and high wind speed events on aerosol number concentrations, size distributions, optical properties and cloud condensation nuclei (CCN) concentrations. Total aerosol number concentrations were significantly enhanced during high-wind speed periods, also concurrent with increased scattering aerosol coefficients and CCN concentrations. We further present a process-based characterization of the blowing snow events during MOSAiC and identify the influence of environmental variables on aerosol emissions. Our observations provide new insights into wind-driven aerosol in the central Arctic and may help to validate modelling studies and inform parameterization improvement particularly with respect to aerosol direct and indirect radiative forcing.</p>