Research Article

Global atmospheric particle formation from CERN CLOUD measurements

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Science  02 Dec 2016:
Vol. 354, Issue 6316, pp. 1119-1124
DOI: 10.1126/science.aaf2649
  • Fig. 1 Measured and parameterized nucleation rates.

    Neutral, GCR, and pion-beam nucleation rates (J) are shown at 1.7 nm mobility diameter as a function of sulfuric acid concentration. Rates are shown at (A) 208, (B) 223, (C) 248, (D) 278, and (E) 292 K. The symbols show measured values of nucleation rates: circles for neutral (n) rates (ion-pair production rate q = 0 cm3 s1), triangles for GCR rates (q = 2 cm3 s1), and squares for pion beam (π) rates (q ~ 75 cm3 s1). The lines show parameterized nucleation rates (supplementary materials, section 8): solid lines for neutral rates, dashed lines for GCR rates, and dotted lines for pion beam rates. Gray symbols and lines indicate contaminant concentrations of NH3 below the detection limit of the instruments (supplementary materials, section 6), whereas colored symbols and lines represent measurements at NH3 concentrations indicated by the color scale. For clarity, the uncertainties on each data point are not shown, but the overall uncertainty of a factor of 2.5 on nucleation rate and a factor of 1.5 on [H2SO4] is shown separately from the real data in (A). The contaminant level of ammonia increases as temperature increases. This explains why the ionization effect without added ammonia at 292 K is smaller than that at 278 K and why the nucleation rates without added ammonia are similar at these temperatures.

  • Fig. 2 Modeled zonal and annual mean particle formation rates, per cubic centimeter per second, at 3 nm diameter.

    (A) Binary (H2SO4-H2O) neutral nucleation rate, (B) binary ion-induced nucleation rate, (C) ternary (H2SO4-NH3-H2O) neutral nucleation rate, (D) ternary ion-induced nucleation rate, (E) ion-induced fraction of inorganic nucleation, and (F) fraction of all nucleation from ternary organic nucleation (H2SO4-BioOxOrg-H2O). In (E) and (F), the model data are shown only where the overall mean nucleation rate exceeds 106 cm3 s1.

  • Fig. 3 Comparison of measured and modeled particle concentrations by latitude and altitude.

    (A) Measured 3-nm-diameter particle concentrations (fig. S17) (44). (B) Modeled particle concentrations (all processes). (C) Modeled particle concentrations including only primary particle emissions and binary neutral nucleation of sulfuric acid and water. Modeled particle concentrations in (C) are much higher than the concentrations that result from the binary-only pathway in the full model because the losses due to the condensation sink for these particles in the full model are higher than those in the binary-only model.

  • Fig. 4 Modeled present-day CCN concentrations and the effect of perturbations.

    Here hygroscopic particles above 70 nm diameter are used as a proxy for CCN. (A) Annual mean CCN concentrations at about cloud base altitude (915 hPa) (N 70, soluble particles with diameters greater than 70 nm). (B) Effect of changing the heliospheric modulation potential from solar minimum to maximum. (C) Effect of reducing ammonia concentrations to preindustrial levels. Perturbations are shown as percentage changes from the baseline shown in (A) where concentrations are higher than 5 cm3.

Supplementary Materials

  • Global atmospheric particle formation from CERN CLOUD measurements

    Eimear M. Dunne, Hamish Gordon, Andreas Kürten, João Almeida, Jonathan Duplissy, Christina Williamson, Ismael K. Ortega, Kirsty J. Pringle, Alexey Adamov, Urs Baltensperger, Peter Barmet, Francois Benduhn, Federico Bianchi, Martin Breitenlechner, Antony Clarke, Joachim Curtius, Josef Dommen, Neil M. Donahue, Sebastian Ehrhart, Richard C. Flagan, Alessandro Franchin, Roberto Guida, Jani Hakala, Armin Hansel, Martin Heinritzi, Tuija Jokinen, Juha Kangasluoma, Jasper Kirkby, Markku Kulmala, Agnieszka Kupc, Michael J. Lawler, Katrianne Lehtipalo, Vladimir Makhmutov, Graham Mann, Serge Mathot, Joonas Merikanto, Pasi Miettinen, Athanasios Nenes, Antti Onnela, Alexandru Rap, Carly L. S. Reddington, Francesco Riccobono, Nigel A. D. Richards, Matti P. Rissanen, Linda Rondo, Nina Sarnela, Siegfried Schobesberger, Kamalika Sengupta, Mario Simon, Mikko Sipilä, James N. Smith, Yuri Stozkhov, Antonio Tomé, Jasmin Tröstl, Paul E. Wagner, Daniela Wimmer, Paul M. Winkler, Douglas R. Worsnop, Kenneth S. Carslaw

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Figs. S1 to S21
    • Tables S1 to S7
    • Caption for Data S1
    • References

    Additional Data

    Data S1
    A table in comma-separated-value format containing the nucleation rates we use in our parameterization of inorganic nucleation is provided. It contains nucleation rate (in cm–3s–1), and the corresponding values of temperature, in Kelvin, sulfuric acid concentration in units of 106 cm–3, ammonia concentration in parts per trillion, ionization rate (cm–3s–1), and relative humidity (in %).

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