Primary marine aerosol‐cloud interactions off the coast of California
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/s1) lasting 8 days, and 71 cm−3 during a period of higher wind speeds (average 16 m/s1) 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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 14, 2015
- Source ID
- 10.1002/2014jd022963
Entities
People
- A. A. Frossard
- A. K. Bertram
- A. K. Y. Lee
- A. M. Macdonald
- A. Nenes
- A. Sorooshian
- A. Wonaschütz
- C. E. Corrigan
- D. Toom‐sauntry
- G. C. Roberts
- H. Jónsson
- J. C. Schroder
- J. H. Seinfeld
- J. P. D. Abbatt
- Jian Lin
- K. J. Noone
- L. Ahlm
- L. M. Russell
- L. N. Hawkins
- R. L. Modini
- Ruoyu Zhao
- W. R. Leaitch
- Zhongbao Wang
Organizations
- California Institute of Technology
- Georgia Tech
- Harvey Mudd College
- National Science Foundation
- Office of Naval Research
- Stockholm University
- Swiss Federal Institute of Technology in Lausanne
- United States Department of Energy
- University of Arizona
- University of British Columbia
- University of California, San Diego
- University of Colorado Boulder
- University of Toronto
- University of Vienna