Ice nucleation and droplet formation by bare and coated soot particles
We have studied ice formation at temperatures relevant to homogeneous and heterogeneous ice nucleation, as well as droplet activation and hygroscopicity, of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied in order to span an atmospherically rel...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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American Geophysical Union (AGU)
2012
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| Online Access: | http://hdl.handle.net/1721.1/74020 https://orcid.org/0000-0003-1851-8740 |
| _version_ | 1811068802016739328 |
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| author | Friedman, Beth Kulkarni, Gourihar Beranek, Josef Zelenyuk, Alla Thornton, Joel A. Cziczo, Daniel James |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Friedman, Beth Kulkarni, Gourihar Beranek, Josef Zelenyuk, Alla Thornton, Joel A. Cziczo, Daniel James |
| author_sort | Friedman, Beth |
| collection | MIT |
| description | We have studied ice formation at temperatures relevant to homogeneous and heterogeneous ice nucleation, as well as droplet activation and hygroscopicity, of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied in order to span an atmospherically relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone in order to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation, with a comparison to a mineral dust particle that acts as an efficient ice nucleus, and particle hygroscopicity. At 253 K and 243 K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, only droplet formation was observed. At 233 K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude that both uncoated and coated soot particles comparable to those generated in our studies are unlikely to significantly contribute to the global budget of heterogeneous ice nuclei at temperatures between 233 K and 253 K. |
| first_indexed | 2024-09-23T08:01:24Z |
| format | Article |
| id | mit-1721.1/74020 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:01:24Z |
| publishDate | 2012 |
| publisher | American Geophysical Union (AGU) |
| record_format | dspace |
| spelling | mit-1721.1/740202022-09-30T01:45:32Z Ice nucleation and droplet formation by bare and coated soot particles Friedman, Beth Kulkarni, Gourihar Beranek, Josef Zelenyuk, Alla Thornton, Joel A. Cziczo, Daniel James Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Cziczo, Daniel James We have studied ice formation at temperatures relevant to homogeneous and heterogeneous ice nucleation, as well as droplet activation and hygroscopicity, of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied in order to span an atmospherically relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone in order to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation, with a comparison to a mineral dust particle that acts as an efficient ice nucleus, and particle hygroscopicity. At 253 K and 243 K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, only droplet formation was observed. At 233 K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude that both uncoated and coated soot particles comparable to those generated in our studies are unlikely to significantly contribute to the global budget of heterogeneous ice nuclei at temperatures between 233 K and 253 K. 2012-10-16T15:07:34Z 2012-10-16T15:07:34Z 2011-09 2011-06 Article http://purl.org/eprint/type/JournalArticle 0148-0227 http://hdl.handle.net/1721.1/74020 Friedman, Beth et al. “Ice Nucleation and Droplet Formation by Bare and Coated Soot Particles.” Journal of Geophysical Research 116.D17 (2011). ©2011. American Geophysical Union https://orcid.org/0000-0003-1851-8740 en_US http://dx.doi.org/10.1029/2011jd015999 Journal of Geophysical Research Atmospheres Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Geophysical Union (AGU) MIT web domain |
| spellingShingle | Friedman, Beth Kulkarni, Gourihar Beranek, Josef Zelenyuk, Alla Thornton, Joel A. Cziczo, Daniel James Ice nucleation and droplet formation by bare and coated soot particles |
| title | Ice nucleation and droplet formation by bare and coated soot particles |
| title_full | Ice nucleation and droplet formation by bare and coated soot particles |
| title_fullStr | Ice nucleation and droplet formation by bare and coated soot particles |
| title_full_unstemmed | Ice nucleation and droplet formation by bare and coated soot particles |
| title_short | Ice nucleation and droplet formation by bare and coated soot particles |
| title_sort | ice nucleation and droplet formation by bare and coated soot particles |
| url | http://hdl.handle.net/1721.1/74020 https://orcid.org/0000-0003-1851-8740 |
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