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Organic Condensation and Particle Growth to CCN Sizes in the Summertime Marine Arctic Is Driven by Materials More Semivolatile Than at Continental Sites
Author(s) -
Burkart Julia,
Hodshire Anna L.,
Mungall Emma L.,
Pierce Jeffrey R.,
Collins Douglas B.,
Ladino Luis A.,
Lee Alex K. Y.,
Irish Victoria,
Wentzell Jeremy J. B.,
Liggio John,
Papakyriakou Tim,
Murphy Jennifer,
Abbatt Jonathan
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl075671
Subject(s) - aerosol , cloud condensation nuclei , nucleation , arctic , atmospheric sciences , isoprene , condensation , particle (ecology) , environmental science , middle latitudes , particle number , sea spray , sulfate , oceanography , chemistry , meteorology , geology , physics , thermodynamics , organic chemistry , volume (thermodynamics) , copolymer , polymer
Ship‐based aerosol measurements in the summertime Arctic indicate elevated concentrations of ultrafine particles with occasional growth to cloud condensation nuclei (CCN) sizes. Focusing on one episode with two continuously growing modes, growth occurs faster for a large, preexisting mode (dp ≈ 90 nm) than for a smaller nucleation mode (dp ≈ 20 nm). We use microphysical modeling to show that growth is largely via organic condensation. Unlike results for midlatitude forested regions, most of these condensing species behave as semivolatile organics, as lower volatility organics would lead to faster growth of the smaller mode. The magnitude of the CCN hygroscopicity parameter for the growing particles, ~0.1, is also consistent with organic species constituting a large fraction of the particle composition. Mixing ratios of common aerosol growth precursors, such as isoprene and sulfur dioxide, are not elevated during the episode, indicating that an unidentified aerosol growth precursor is present in this high‐latitude marine environment.