Atmospheric particle abundance and sea salt aerosol observations in the springtime Arctic: a focus on blowing snow and leads

Abstract

Abstract. Sea salt aerosols play an important role in the radiation budget and atmospheric composition over the Arctic, where the climate is rapidly changing. Previous observational studies have shown that Arctic sea ice leads are an important source of sea salt aerosols, and modeling efforts have also proposed blowing snow sublimation as a source. In this study, size-resolved atmospheric particle number concentrations and chemical composition were measured at the Arctic coastal tundra site of Utqiaġvik, Alaska, during spring (3 April–7 May 2016). Blowing snow conditions were observed during 25 % of the 5-week study period and were overpredicted by a commonly used blowing snow parameterization based solely on wind speed and temperature. Throughout the study, open leads were present locally. During periods when blowing snow was observed, significant increases in the number concentrations of 0.01–0.06 µm particles (factor of 6, on average) and 0.06–0.3 µm particles (67 %, on average) and a significant decrease (82 %, on average) in 1–4 µm particles were observed compared to low wind speed periods. These size distribution changes were likely caused by the generation of ultrafine particles from leads and/or blowing snow, with scavenging of supermicron particles by blowing snow. At elevated wind speeds, both submicron and supermicron sodium and chloride mass concentrations were enhanced, consistent with wind-dependent local sea salt aerosol production. At moderate wind speeds below the threshold for blowing snow as well as during observed blowing snow, individual sea spray aerosol particles were measured. These individual salt particles were enriched in calcium relative to sodium in seawater due to the binding of this divalent cation with organic matter in the sea surface microlayer and subsequent enrichment during seawater bubble bursting. The chemical composition of the surface snowpack also showed contributions from sea spray aerosol deposition. Overall, these results show the contribution of sea spray aerosol production from leads on both aerosols and the surface snowpack. Therefore, if blowing snow sublimation contributed to the observed sea salt aerosol, the snow being sublimated would have been impacted by sea spray aerosol deposition rather than upward brine migration through the snowpack. Sea spray aerosol production from leads is expected to increase, with thinning and fracturing of sea ice in the rapidly warming Arctic.

Glucose Enhances Salinity-Driven Sea Spray Aerosol Production in Eastern Arctic Waters

“…Sellegri et al and Fuentes et al found the 300 nm mode in air-forced bubble bursting chamber experiments with seawater samples from the Mediterranean Sea and around New Zealand. The 30 nm mode was also found in other studies in several regions ,, including the Arctic . We hypothesize that these observed modes are related to the composition of the particles, as discussed later.…”

“…The 30 nm mode was also found in other studies in several regions 68 , 70 , 71 including the Arctic. 72 We hypothesize that these observed modes are related to the composition of the particles, as discussed later.…”

Arctic warming by abundant fine sea salt aerosols from blowing snow

“…Therefore, the conventional thinking is that while SSAs often contribute substantially to or even dominate high-latitude aerosol mass concentration 14 , 15 and direct radiative effect 26 , their influences on CCN concentration ( N CCN ) and cloud properties are less pronounced 25 , 26 . A recent modelling study in the Antarctic suggests blowing-snow sublimation may generate a substantial amount of fine-mode particles 27 , and elevated concentrations of fine-mode particles during blowing-snow events at a coastal Alaskan Arctic site are reported in a recent observational study 28 . Both studies raise the possibility that blowing-snow-produced SSA may strongly affect the Arctic climate by impacting the CCN population and the properties of clouds.…”

Marine carbohydrates in Arctic aerosol particles and fog – diversity of oceanic sources and atmospheric transformations

“…Finally, blowing snow over the sea ice could serve as an additional source of atmospheric Na + aer when a certain air-temperature-dependent wind speed threshold is exceeded (Chen et al, 2022;Huang and Jaeglé, 2017;Yang et al, 2008). Consequently, connections and correlations for the release of SSA particles in the heterogeneous high Arctic are more difficult to explore than other marine environments without sea ice.…”