CCN Activity, Variability and Influence on Droplet Formation during the HygrA-Cd Campaign in Athens
| Autor: | Stavros Solomos, Konstantinos Eleftheriadis, Stergios Vratolis, Athanasios Nenes, Athina Argyrouli, Aikaterini Bougiatioti, Alexandros Papayannis |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences Aerosol size distributions aerosol CCN activity droplet formation cloud maximum supersaturation relative contribution of updraft velocity Velocity spatial variation 010501 environmental sciences Atmospheric sciences 01 natural sciences Urban background size distribution Supersaturation Relative contribution concentration (composition) Greece Aerosol particle concentrations Size distribution measurements Boundary layer Atmospheric dynamics Drops atmospheric dynamics Meteorology supersaturation hygroscopicity Urban growth Cloud droplet number Environmental Science (miscellaneous) lcsh:QC851-999 Cloud droplet Boundary layer dynamics Cloud condensation nuclei Atmospheric movements cloud condensation nucleus updraft 0105 earth and related environmental sciences Aerosols formation mechanism Aerosol Athens [Attica] 13. Climate action Attica Environmental science droplet lcsh:Meteorology. Climatology Drop formation |
| Zdroj: | Atmosphere, Vol 8, Iss 6, p 108 (2017) Atmosphere Atmosphere; Volume 8; Issue 6; Pages: 108 |
| ISSN: | 2073-4433 |
| Popis: | Measurements of cloud condensation nuclei (CCN) concentrations (cm−3 ) at five levels of supersaturation between 0.2–1%, together with remote sensing profiling and aerosol size distributions, were performed at an urban background site of Athens during the Hygroscopic Aerosols to Cloud Droplets (HygrA-CD) campaign. The site is affected by local emissions and long-range transport, as portrayed by the aerosol size, hygroscopicity and mixing state. Application of a state-of-the-art droplet parameterization is used to link the observed size distribution measurements, bulk composition, and modeled boundary layer dynamics with potential supersaturation, droplet number, and sensitivity of these parameters for clouds forming above the site. The sensitivity is then used to understand the source of potential droplet number variability. We find that the importance of aerosol particle concentration levels associated with the background increases as vertical velocities increase. The updraft velocity variability was found to contribute 58–90% (68.6% on average) to the variance of the cloud droplet number, followed by the variance in aerosol number (6–32%, average 23.2%). Therefore, although local sources may strongly modulate CCN concentrations, their impact on droplet number is limited by the atmospheric dynamics expressed by the updraft velocity regime. |
| Databáze: | OpenAIRE |
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