Primary marine aerosol‐cloud interactions off the coast of California

Journal Article · Thu May 14 04:00:00 EDT 2015 · Journal of Geophysical Research: Atmospheres

DOI:https://doi.org/10.1002/2014JD022963· OSTI ID:1402357

Modini, R. L. ^[1]; Frossard, A. A. ^[2]; Ahlm, L. ^[3]; Russell, L. M. ^[4]; Corrigan, C. E. ^[4]; Roberts, G. C. ^[5]; Hawkins, L. N. ^[6]; Schroder, J. C. ^[7]; Bertram, A. K. ^[8]; Zhao, R. ^[9]; Lee, A. K. Y. ^[9]; Abbatt, J. P. D. ^[9]; Lin, J. ^[10]; Nenes, A. ^[11]; Wang, Z. ^[12]; Wonaschütz, A. ^[13]; Sorooshian, A. ^[12]; Noone, K. J. ^[14]; Jonsson, H. ^[15]; Seinfeld, J. H. ^[16] ; Toom‐Sauntry, D. ^[17]; Macdonald, A. M. ^[17]; Leaitch, W. R. ^[17]

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1. Scripps Institution of Oceanography University of California, San Diego La Jolla California USA, Now at École Polytechnique Fédérale de Lausanne Lausanne Switzerland
2. Scripps Institution of Oceanography University of California, San Diego La Jolla California USA, Now at Department of Chemistry University of California Berkeley California USA
3. Scripps Institution of Oceanography University of California, San Diego La Jolla California USA, Now at Department of Applied Environmental Science (ITM) and the Bolin Centre for Climate Research Stockholm University Stockholm Sweden
4. Scripps Institution of Oceanography University of California, San Diego La Jolla California USA
5. Scripps Institution of Oceanography University of California, San Diego La Jolla California USA, Centre National de la Recherche Scientifique‐Groupe d'études de l'Atmosphère Météorologique Toulouse France
6. Department of Chemistry Harvey Mudd College Claremont California USA
7. Department of Chemistry University of British Columbia Vancouver British Columbia Canada, Now at Department of Chemistry and Biochemistry and CIRES University of Colorado Boulder Boulder Colorado USA
8. Department of Chemistry University of British Columbia Vancouver British Columbia Canada
9. Department of Chemistry University of Toronto Toronto Ontario Canada
10. School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta Georgia USA
11. School of Earth and Atmospheric Sciences, and School of Chemical and Biomolecular Engineering Georgia Institute of Technology Atlanta Georgia USA
12. Department of Chemical and Environmental Engineering, and Department of Atmospheric Sciences University of Arizona Tucson Arizona USA
13. Faculty of Physics University of Vienna Vienna Austria
14. Department of Applied Environmental Science Stockholm University Stockholm Sweden
15. Center for Interdisciplinary Remotely‐Piloted Aerosol Studies Marina California USA
16. Department of Chemical Engineering California Institute of Technology Pasadena California USA
17. Science and Technology Branch Environment Canada Toronto Ontario Canada

Abstract

Primary marine aerosol (PMA)‐cloud interactions off the coast of California were investigated using observations of marine aerosol, cloud condensation nuclei (CCN), and stratocumulus clouds during the Eastern Pacific Emitted Aerosol Cloud Experiment (E‐PEACE) and the Stratocumulus Observations of Los‐Angeles Emissions Derived Aerosol‐Droplets (SOLEDAD) studies. Based on recently reported measurements of PMA size distributions, a constrained lognormal‐mode‐fitting procedure was devised to isolate PMA number size distributions from total aerosol size distributions and applied to E‐PEACE measurements. During the 12 day E‐PEACE cruise on the R/V Point Sur , PMA typically contributed less than 15% of total particle concentrations. PMA number concentrations averaged 12 cm ⁻³ during a relatively calmer period (average wind speed 12 m/s ¹ ) lasting 8 days, and 71 cm ⁻³ during a period of higher wind speeds (average 16 m/s ¹ ) lasting 5 days. On average, PMA contributed less than 10% of total CCN at supersaturations up to 0.9% during the calmer period; however, during the higher wind speed period, PMA comprised 5–63% of CCN (average 16–28%) at supersaturations less than 0.3%. Sea salt was measured directly in the dried residuals of cloud droplets during the SOLEDAD study. The mass fractions of sea salt in the residuals averaged 12 to 24% during three cloud events. Comparing the marine stratocumulus clouds sampled in the two campaigns, measured peak supersaturations were 0.2 ± 0.04% during E‐PEACE and 0.05–0.1% during SOLEDAD. The available measurements show that cloud droplet number concentrations increased with >100 nm particles in E‐PEACE but decreased in the three SOLEDAD cloud events.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0006679
• OSTI ID: 1402357
• Journal Information: Journal of Geophysical Research: Atmospheres, Journal Name: Journal of Geophysical Research: Atmospheres Journal Issue: 9 Vol. 120; ISSN 2169-897X
• Publisher: American Geophysical Union (AGU)
• Country of Publication: United States
• Language: English