Atmospheric particle abundance and sea salt aerosol observations in the springtime Arctic: a focus on blowing snow and leads
- 1Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- 2Department of Meteorology and Atmospheric Science, Pennsylvania State University, University Park, Pennsylvania 16801, United States
- 3Department of Atmospheric Sciences, University of North Dakota, Grand Forks, North Dakota 58202, United States
- 4Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington 98115, United States
- 5Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, Seattle, Washington 98115, United States
- 6Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
- 7Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
- 8Department of Earth, Atmospheric, and Planetary Sciences & Purdue Climate Change Research Center, Purdue University, West Lafayette, Indiana 47907, United States
- 9Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan 48109, United States
- anow at: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China
- bnow at: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794, United States
- cnow at: Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada
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 Arctic sea ice leads to be 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 (April 3 – May 7, 2016). Blowing snow conditions were observed during 25 % of the five-week study period and were over-predicted 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 six, 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 sublimed must 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.
Qianjie Chen et al.
Status: open (until 15 Aug 2022)
Qianjie Chen et al.
Qianjie Chen et al.
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