Enrichment of calcium in sea spray aerosol: insights from bulk measurements and individual particle analysis during the R/V Xuelong cruise in the summertime in Ross Sea, Antarctica

• Published in: Atmospheric Chemistry and Physics
• Main Authors: B. Su, X. Bi, Z. Zhang, Y. Liang, C. Song, T. Wang, Y. Hu, L. Li, Z. Zhou, J. Yan, X. Wang, G. Zhang
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2023
• Subjects: Physics; QC1-999; Chemistry; QD1-999; Antarc*; Antarctic; Antarctica; Ross Sea; Sea ice
• Online Access: https://doi.org/10.5194/acp-23-10697-2023; https://doaj.org/article/1dfdb30f3dda4039a9e90beb2ece8723

Although calcium is known to be enriched in sea spray aerosols (SSAs), the factors that affect its enrichment remain ambiguous. In this study, we examine how environmental factors affect the distribution of water-soluble calcium (Ca 2+ ) distribution in SSAs. We obtained our dataset from observations taken during the R/V Xuelong research cruise in the Ross Sea, Antarctica, from December 2017 to February 2018. Our observations showed that the enrichment of Ca 2+ in aerosol samples was enhanced under specific conditions, including lower temperatures ( < - 3.5 <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="35pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="a02a53301a96bb7892434dbbb5a8930d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-23-10697-2023-ie00001.svg" width="35pt" height="10pt" src="acp-23-10697-2023-ie00001.png"/></svg:svg> ∘ C), lower wind speeds ( <7 m s −1 ), and the presence of sea ice. Our analysis of individual particle mass spectra revealed that a significant portion of calcium in SSAs was likely bound with organic matter (in the form of a single-particle type, OC-Ca, internally mixed organics with calcium). Our findings suggest that current estimations of Ca 2+ enrichment based solely on water-soluble Ca 2+ may be inaccurate. Our study is the first to observe a single-particle type dominated by calcium in the Antarctic atmosphere. Our findings suggest that future Antarctic atmospheric modeling should take into account the environmental behavior of individual OC-Ca particles. With the ongoing global warming and retreat of sea ice, it is essential to understand the mechanisms of calcium enrichment and the mixing state of individual particles to better comprehend the interactions between aerosols, clouds, and climate during the Antarctic summer.