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Abstract

A likely important feature of the poorly understood aerosol‐cloud interactions over the Southern Ocean (SO) is the dominant role of sea spray aerosol, versus terrestrial aerosol. Ice nucleating particles (INPs), or particles required for heterogeneous ice nucleation, present over the SO have not been studied in several decades. In this study, boundary layer aerosol properties and immersion freezing INP number concentrations (nINPs) were measured during a ship campaign that occurred south of Australia (down to 53 °S) in March‐April 2016. Ocean surface chlorophyll‐a concentrations ranged from 0.11‐1.77 mg m‐3 and nINPs were a factor of 100 lower than historical surveys, ranging from 0.38 to 4.6 m‐3 at ‐20 °C. The INP population included organic heat‐stable material, with contributions from heat‐labile material. Lower INP source potentials of SO seawater samples compared to Arctic seawater were consistent with lower ice nucleating site densities in this study compared to north Atlantic air masses.

Item Type:	Article
Authors/Creators:	McCluskey, CS and Hill, TCJ and Humphries, RS and Rauker, AM and Moreau, S and Strutton, PG and Chambers, SD and Williams, AG and McRobert, I and Ward, J and Keywood, MD and Harnwell, J and Ponsonby, W and Loh, ZM and Krummel, PB and Protat, A and Kreidenweis, SM and DeMott, PJ
Keywords:	ice nucleating particles, marine organic aerosol, Southern Ocean
Journal or Publication Title:	Geophysical Research Letters
Publisher:	Amer Geophysical Union
ISSN:	0094-8276
DOI / ID Number:	https://doi.org/10.1029/2018GL079981
Copyright Information:	©2018. American Geophysical Union
Related URLs:	Google Scholar: Moreau, S Google Scholar: Strutton, PG UTAS Profile: Strutton, PG
Item Statistics:	View statistics for this item

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