Technical note: Phase space depiction of cloud condensation nuclei activation and cloud droplet diffusional growth
<p>A novel way to represent cloud condensation nuclei (CCN) activation and cloud droplet growth by the diffusion of water vapor is introduced. The key is to apply a phase space diagram that plots the radius of a liquid droplet (deliquesced CCN or cloud droplet) versus the difference between th...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2025-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/25/5273/2025/acp-25-5273-2025.pdf |
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| author | W. W. Grabowski H. Pawlowska |
| author_facet | W. W. Grabowski H. Pawlowska |
| author_sort | W. W. Grabowski |
| collection | DOAJ |
| description | <p>A novel way to represent cloud condensation nuclei (CCN) activation and cloud droplet growth by the diffusion of water vapor is introduced. The key is to apply a phase space diagram that plots the radius of a liquid droplet (deliquesced CCN or cloud droplet) versus the difference between the ambient supersaturation and the equilibrium supersaturation corresponding to the droplet radius. The latter combines the droplet and environmental characteristics, and it determines whether a droplet grows or evaporates. The diagram can be used to depict (in a straightforward way) key microphysical processes of CCN activation and deactivation as well as haze or cloud droplet transition from growth to evaporation. To show its utility, the diagram is applied to an idealized simulation of CCN activation and cloud droplet growth inside a rising turbulent air parcel and to simulations of microphysical processes inside a laboratory apparatus, the Pi cloud chamber. The adiabatic parcel mimics microphysical processes near the base of a natural cumulus or stratocumulus cloud. The Pi chamber simulations represent microphysical transformations in moist turbulent Rayleigh–Bénard convection with CCN proceeding through cycles of activation, growth, evaporation, and deactivation. A more general version of the phase diagram that is independent of the CCN dry radius is also developed. The phase diagram allows simple interpretations of key microphysical processes and highlights differences between droplet formation in natural and laboratory clouds.</p> |
| format | Article |
| id | doaj-art-a2659b2ef0ef4bee88ceeaeb98893856 |
| institution | DOAJ |
| issn | 1680-7316 1680-7324 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj-art-a2659b2ef0ef4bee88ceeaeb988938562025-08-20T03:09:03ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242025-05-01255273528510.5194/acp-25-5273-2025Technical note: Phase space depiction of cloud condensation nuclei activation and cloud droplet diffusional growthW. W. Grabowski0H. Pawlowska1MMM Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USAInstitute of Geophysics, Faculty of Physics, University of Warsaw, Warsaw, Poland<p>A novel way to represent cloud condensation nuclei (CCN) activation and cloud droplet growth by the diffusion of water vapor is introduced. The key is to apply a phase space diagram that plots the radius of a liquid droplet (deliquesced CCN or cloud droplet) versus the difference between the ambient supersaturation and the equilibrium supersaturation corresponding to the droplet radius. The latter combines the droplet and environmental characteristics, and it determines whether a droplet grows or evaporates. The diagram can be used to depict (in a straightforward way) key microphysical processes of CCN activation and deactivation as well as haze or cloud droplet transition from growth to evaporation. To show its utility, the diagram is applied to an idealized simulation of CCN activation and cloud droplet growth inside a rising turbulent air parcel and to simulations of microphysical processes inside a laboratory apparatus, the Pi cloud chamber. The adiabatic parcel mimics microphysical processes near the base of a natural cumulus or stratocumulus cloud. The Pi chamber simulations represent microphysical transformations in moist turbulent Rayleigh–Bénard convection with CCN proceeding through cycles of activation, growth, evaporation, and deactivation. A more general version of the phase diagram that is independent of the CCN dry radius is also developed. The phase diagram allows simple interpretations of key microphysical processes and highlights differences between droplet formation in natural and laboratory clouds.</p>https://acp.copernicus.org/articles/25/5273/2025/acp-25-5273-2025.pdf |
| spellingShingle | W. W. Grabowski H. Pawlowska Technical note: Phase space depiction of cloud condensation nuclei activation and cloud droplet diffusional growth Atmospheric Chemistry and Physics |
| title | Technical note: Phase space depiction of cloud condensation nuclei activation and cloud droplet diffusional growth |
| title_full | Technical note: Phase space depiction of cloud condensation nuclei activation and cloud droplet diffusional growth |
| title_fullStr | Technical note: Phase space depiction of cloud condensation nuclei activation and cloud droplet diffusional growth |
| title_full_unstemmed | Technical note: Phase space depiction of cloud condensation nuclei activation and cloud droplet diffusional growth |
| title_short | Technical note: Phase space depiction of cloud condensation nuclei activation and cloud droplet diffusional growth |
| title_sort | technical note phase space depiction of cloud condensation nuclei activation and cloud droplet diffusional growth |
| url | https://acp.copernicus.org/articles/25/5273/2025/acp-25-5273-2025.pdf |
| work_keys_str_mv | AT wwgrabowski technicalnotephasespacedepictionofcloudcondensationnucleiactivationandclouddropletdiffusionalgrowth AT hpawlowska technicalnotephasespacedepictionofcloudcondensationnucleiactivationandclouddropletdiffusionalgrowth |