Marine and Terrestrial Organic Ice‐Nucleating Particles in Pristine Marine to Continentally Influenced Northeast Atlantic Air Masses. Issue 11 (15th June 2018)

• Record Type: Journal Article
• Authors: McCluskey, Christina S.; Ovadnevaite, Jurgita; Rinaldi, Matteo; Atkinson, James; Belosi, Franco; Ceburnis, Darius; Marullo, Salvatore; Hill, Thomas C. J.; Lohmann, Ulrike; Kanji, Zamin A.; O'Dowd, Colin; Kreidenweis, Sonia M.; DeMott, Paul J.
• Is Part Of: Journal of geophysical research. Volume 123:Issue 11(2018)
• Page Start: 6196
• Page End: 6212
• Publication Date: 2018-06-15
• Subjects: marine ice‐nucleating particles -- marine organic aerosol -- sea spray aerosol -- marine ice‐nucleating particle parameterization -- ice‐nucleating particles; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2017JD028033
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Sea spray aerosol (SSA) generated by bubble bursting at the ocean surface is an important component of aerosol‐cloud interactions over remote oceans, providing the atmosphere with ice‐nucleating particles (INPs) or particles required for heterogeneous ice nucleation. Studies have shown that organic INPs are emitted during phytoplankton blooms, but changes in INP number concentrations ( n INPs ) due to ocean biological activity have not been directly demonstrated in natural SSA. In this study, a clean sector sampler was used to differentiate ice nucleation and composition of pristine SSA from terrestrial aerosol at the Mace Head Research Station in August 2015. Average n INPs active at −15 °C ( n INPs, −15 °C ) were 0.0011 L −1, and large variability (up to a factor of 200) was observed for INPs active warmer than −22 °C. Highest n INPs in the clean sector occurred during a period of elevated marine organic aerosol from offshore biological activity (M1, n INPs, − 15 °C = 0.0077 L −1 ). A peak in n INPs was also observed in terrestrial organic aerosol (T1, n INPs, − 15 °C = 0.0076 L −1 ). The impacts of heating and hydrogen peroxide digestion on n INPs indicate that INPs at Mace Head Research Station were largely organic and that INPs observed during M1 and T1 were biological (i.e., protein containing). Complexities of predicting increases in n INPs due to offshore biological activity are explored. A parameterization for pristine SSA INPs over the North Atlantic Ocean was developed, illustrating that SSA is associated with a factor of 1, 000 fewer ice‐nucleating sites per surface area of aerosol compared to mineral dust. Key Points: Pristine sea spray aerosol is a dominant regional source of ice‐nucleating particles at a remote North Atlantic coastal site Ice‐nucleating particles at a remote North Atlantic coastal site were largely composed of organic carbon and/or heat labile material Sea spray aerosol is associated with a factor of 1, 000 fewer ice‐nucleating sites per surface area of aerosol compared to mineral dust