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Primary marine aerosol-cloud interactions off the coast of California

Modini, R. L. and Frossard, A. A. and Ahlm, L. and Russell, L. M. and Corrigan, C. E. and Roberts, G. C. and Hawkins, L. N. and Schroder, J. C. and Bertram, A. K. and Zhao, R. and Lee, A. K. Y. and Abbatt, J. P. D. and Lin, J. and Nenes, A. and Wang, Z. and Wonaschütz, A. and Sorooshian, A. and Noone, K. J. and Jonsson, H. and Seinfeld, J. H. and Toom-Sauntry, D. and Macdonald, A. M. and Leaitch, W. R. (2015) Primary marine aerosol-cloud interactions off the coast of California. Journal of Geophysical Research. Atmospheres, 120 (9). pp. 4282-4303. ISSN 2169-897X.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription Information
Modini, R. L.0000-0002-2982-1369
Frossard, A. A.0000-0002-5728-0854
Russell, L. M.0000-0002-6108-2375
Roberts, G. C.0000-0002-3636-8590
Nenes, A.0000-0003-3873-9970
Wang, Z.0000-0002-7921-3134
Sorooshian, A.0000-0002-2243-2264
Jonsson, H.0000-0003-3043-1074
Seinfeld, J. H.0000-0003-1344-4068
Additional Information:© 2015 American Geophysical Union. Received 8 Dec 2014; Accepted 13 Apr 2015; Accepted article online 16 Apr 2015; Published online 14 May 2015. This work was funded by NSF AGS-1360645, NSF AGS-1013423, NSF AGS-1008848, DOE DE-SC0006679, and ONR grants N00014-11-1-0783, N00014-10-1-0200, and N00014-10-1-0811. R.L.M. appreciates the support of the Scripps Postdoctoral Scholars program. We gratefully acknowledge the help and support of the crew and staff of the R/V Point Sur and the CIRPAS Twin Otter, as well as assistance from Janin Guzman-Morales, Ashley Corrigan, Bill Shull, and Ken Duff of Scripps Institution of Oceanography. To obtain the data used in this study please go to or contact the corresponding author (
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0006679
Office of Naval Research (ONR)N00014-11-1-0783
Office of Naval Research (ONR)N00014-10-1-0200
Office of Naval Research (ONR)N00014-10-1-0811
Scripps Institution of OceanographyUNSPECIFIED
Subject Keywords:sea spray aerosol; marine aerosol; cloud condensation nuclei; stratocumulus clouds; supersaturations; aerosol-cloud interactions
Issue or Number:9
Record Number:CaltechAUTHORS:20150702-131234390
Persistent URL:
Official Citation:Modini, R. L., Frossard, A. A., Ahlm, L., Russell, L. M., Corrigan, C. E., Roberts, G. C., . . . Leaitch, W. R. (2015). Primary marine aerosol-cloud interactions off the coast of California. Journal of Geophysical Research: Atmospheres, 120(9), 2014JD022963. doi: 10.1002/2014jd022963
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:58757
Deposited By: Joanne McCole
Deposited On:02 Jul 2015 21:08
Last Modified:09 Mar 2020 13:19

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