Organic enrichment in droplet residual particles relative to out of cloud over the northwestern Atlantic: analysis of airborne ACTIVATE data
-
Published:2022-10-28
Issue:20
Volume:22
Page:13897-13913
-
ISSN:1680-7324
-
Container-title:Atmospheric Chemistry and Physics
-
language:en
-
Short-container-title:Atmos. Chem. Phys.
Author:
Dadashazar Hossein, Corral Andrea F., Crosbie Ewan, Dmitrovic SanjaORCID, Kirschler SimonORCID, McCauley Kayla, Moore RichardORCID, Robinson Claire, Schlosser Joseph S.ORCID, Shook MichaelORCID, Thornhill K. Lee, Voigt ChristianeORCID, Winstead Edward, Ziemba Luke, Sorooshian ArminORCID
Abstract
Abstract. Cloud processing is known to generate aerosol species such as sulfate and secondary organic aerosol, yet there is a scarcity of airborne data to
examine this issue. The NASA Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) was designed to build an
unprecedented dataset relevant to aerosol–cloud interactions with two coordinated aircraft over the northwestern Atlantic, with aerosol mass spectrometer data used from four deployments between 2020–2021 to contrast aerosol composition below, in (using a counterflow virtual impactor)
and above boundary layer clouds. Consistent features in all time periods of the deployments (January–March, May–June, August–September) include
the mass fraction of organics and relative amount of oxygenated organics (m/z 44) relative to total organics (f44) increasing in droplet
residuals relative to below and above cloud. Detailed analysis comparing data below and in cloud suggests a possible role for in-cloud aqueous
processing in explaining such results; an intriguing aspect though requiring more attention is that only approximately a quarter of the cloud
cases (29 of 110) showed higher organic mass fractions either below or above cloud. Of those 29 cases, the majority (25) showed higher organic mass
fraction below cloud base where the cloud processing signature is presumably more evident as compared to above cloud. These results are consistent
with the few past studies analyzing droplet residuals pointing to higher organic enrichment than in adjacent cloud-free areas. The data findings are
important as other datasets (e.g., reanalysis) suggest that sulfate is both more abundant than organics (in contrast to this work) and more closely
related to drop number concentrations in the winter when aerosol–cloud interactions are strongest. Here we show that organics are more abundant than
sulfate in the droplet residuals and that aerosol interaction with clouds potentially decreases particle hygroscopicity due to the increase in
organic:sulfate ratio for droplet residuals relative to surrounding cloud-free air. These results are important in light of the growing importance
of organics over the northwestern Atlantic in recent decades relative to sulfate owing to the success of regulatory activity over the eastern United States to cut sulfur dioxide emissions.
Funder
Deutsche Forschungsgemeinschaft Helmholtz Association National Aeronautics and Space Administration
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference68 articles.
1. Aldhaif, A. M., Lopez, D. H., Dadashazar, H., Painemal, D., Peters, A. J., and Sorooshian, A.:
An Aerosol Climatology and Implications for Clouds at a Remote Marine Site: Case Study Over Bermuda, J. Geophys. Res.-Atmos., 126, e2020JD034038, https://doi.org/10.1029/2020JD034038, 2021. 2. Asa-Awuku, A., Sorooshian, A., Flagan, R. C., Seinfeld, J. H., and Nenes, A.:
CCN Properties of Organic Aerosol Collected Below and within Marine Stratocumulus Clouds near Monterey, California, Atmosphere, 6, 1590–1607, 2015. 3. Barth, M. C., Rasch, P. J., Kiehl, J. T., Benkovitz, C. M., and Schwartz, S. E.:
Sulfur chemistry in the National Center for Atmospheric Research Community Climate Model: Description, evaluation, features, and sensitivity to aqueous chemistry, J. Geophys. Res.-Atmos., 105, 1387–1415, https://doi.org/10.1029/1999JD900773, 2000. 4. Bates, T. S., Quinn, P. K., Coffman, D. J., Johnson, J. E., and Middlebrook, A. M.:
Dominance of organic aerosols in the marine boundary layer over the Gulf of Maine during NEAQS 2002 and their role in aerosol light scattering, J. Geophys. Res.-Atmos. 110, D18202, https://doi.org/10.1029/2005JD005797, 2005. 5. Blando, J. D. and Turpin, B. J.:
Secondary organic aerosol formation in cloud and fog droplets: a literature evaluation of plausibility, Atmos. Environ., 34, 1623–1632, https://doi.org/10.1016/S1352-2310(99)00392-1, 2000.
Cited by
3 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|