Reply on RC2

Abstract

<strong class="journal-contentHeaderColor">Abstract.</strong> Calcium is known to be enriched in sea spray aerosols (SSA), but its controlling factors and individual mixing states remain ambiguous. Here, we investigate the impact of various environmental factors on the water-soluble calcium (Ca²⁺) distribution in SSA through R/V <em>Xuelong</em> cruise observations over the Ross Sea, Antarctica, from December 2017 to February 2018. We observed enhanced Ca²⁺ enrichment in aerosol samples at lower temperatures (&lt; -3.5 &deg;C), lower wind speeds (&lt; 7 m s^-1) and in the presence of sea ice. Further individual particle mass spectral analysis indicated that considerable fractions of calcium in SSA likely bind with organic matter (a single-particle type, OC-Ca), which may be neglected in current water-soluble estimation of Ca²⁺ enrichment. Also, this is the first time that a calcium-dominated single-particle type has been observed in the Antarctic atmosphere. We suggest that a broader focus on individual OC-Ca and its subsequent environmental behavior should be included in future Antarctic atmospheric modeling. Given the context of global warming and sea ice retreat, an understanding of the mechanisms of calcium enrichment and mixing state of individual particles involved is valuable for further recognizing the aerosol-cloud-climate interactions in the Antarctica summer.