Relationships between particles, cloud condensation nuclei and cloud droplet activation during the third Pallas Cloud Experiment
Concurrent measurement of aerosols, cloud condensation nuclei (CCN) and cloud droplet activation were carried out as a part of the third Pallas Cloud Experiment (PaCE-3) which took place at a ground based site located on northern Finland during the autumn of 2009. In this study, we investigate relat...
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ftcopernicus:oai:publications.copernicus.org:acp15601 2023-05-15T15:12:30+02:00 Relationships between particles, cloud condensation nuclei and cloud droplet activation during the third Pallas Cloud Experiment Anttila, T. Brus, D. Jaatinen, A. Hyvärinen, A.-P. Kivekäs, N. Romakkaniemi, S. Komppula, M. Lihavainen, H. 2018-01-15 application/pdf https://doi.org/10.5194/acp-12-11435-2012 https://www.atmos-chem-phys.net/12/11435/2012/ eng eng doi:10.5194/acp-12-11435-2012 https://www.atmos-chem-phys.net/12/11435/2012/ eISSN: 1680-7324 Text 2018 ftcopernicus https://doi.org/10.5194/acp-12-11435-2012 2019-12-24T09:55:42Z Concurrent measurement of aerosols, cloud condensation nuclei (CCN) and cloud droplet activation were carried out as a part of the third Pallas Cloud Experiment (PaCE-3) which took place at a ground based site located on northern Finland during the autumn of 2009. In this study, we investigate relationships between the aerosol properties, CCN and size resolved cloud droplet activation. During the investigated cloudy periods, the inferred number of cloud droplets (CDNC) varied typically between 50 and 150 cm −3 and displayed a linear correlation both with the number of particles having sizes over 100 nm and with the CCN concentrations at 0.4% supersaturation. Furthermore, the diameter corresponding to the 50% activation fraction, D 50 , was generally in the range of 80 to 120 nm. The measured CCN concentrations were compared with predictions of a numerical model which used the measured size distribution and size resolved hygroscopicity as input. Assuming that the droplet surface tension is equal to that of water, the measured and predicted CCN concentrations were generally within 30%. We also simulated size dependent cloud droplet activation with a previously developed air parcel model. By forcing the model to reproduce the experimental values of CDNC, adiabatic estimates for the updraft velocity and the maximum supersaturation reached in the clouds were derived. Performed sensitivity studies showed further that the observed variability in CDNC was driven mainly by changes in the particle size distribution while the variations in the updraft velocity and hygroscopicity contributed to a lesser extent. The results of the study corroborate conclusions of previous studies according to which the number of cloud droplets formed in clean air masses close to the Arctic is determined mainly by the number of available CCN. Text Arctic Northern Finland Copernicus Publications: E-Journals Arctic Atmospheric Chemistry and Physics 12 23 11435 11450 |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
Concurrent measurement of aerosols, cloud condensation nuclei (CCN) and cloud droplet activation were carried out as a part of the third Pallas Cloud Experiment (PaCE-3) which took place at a ground based site located on northern Finland during the autumn of 2009. In this study, we investigate relationships between the aerosol properties, CCN and size resolved cloud droplet activation. During the investigated cloudy periods, the inferred number of cloud droplets (CDNC) varied typically between 50 and 150 cm −3 and displayed a linear correlation both with the number of particles having sizes over 100 nm and with the CCN concentrations at 0.4% supersaturation. Furthermore, the diameter corresponding to the 50% activation fraction, D 50 , was generally in the range of 80 to 120 nm. The measured CCN concentrations were compared with predictions of a numerical model which used the measured size distribution and size resolved hygroscopicity as input. Assuming that the droplet surface tension is equal to that of water, the measured and predicted CCN concentrations were generally within 30%. We also simulated size dependent cloud droplet activation with a previously developed air parcel model. By forcing the model to reproduce the experimental values of CDNC, adiabatic estimates for the updraft velocity and the maximum supersaturation reached in the clouds were derived. Performed sensitivity studies showed further that the observed variability in CDNC was driven mainly by changes in the particle size distribution while the variations in the updraft velocity and hygroscopicity contributed to a lesser extent. The results of the study corroborate conclusions of previous studies according to which the number of cloud droplets formed in clean air masses close to the Arctic is determined mainly by the number of available CCN. |
format |
Text |
author |
Anttila, T. Brus, D. Jaatinen, A. Hyvärinen, A.-P. Kivekäs, N. Romakkaniemi, S. Komppula, M. Lihavainen, H. |
spellingShingle |
Anttila, T. Brus, D. Jaatinen, A. Hyvärinen, A.-P. Kivekäs, N. Romakkaniemi, S. Komppula, M. Lihavainen, H. Relationships between particles, cloud condensation nuclei and cloud droplet activation during the third Pallas Cloud Experiment |
author_facet |
Anttila, T. Brus, D. Jaatinen, A. Hyvärinen, A.-P. Kivekäs, N. Romakkaniemi, S. Komppula, M. Lihavainen, H. |
author_sort |
Anttila, T. |
title |
Relationships between particles, cloud condensation nuclei and cloud droplet activation during the third Pallas Cloud Experiment |
title_short |
Relationships between particles, cloud condensation nuclei and cloud droplet activation during the third Pallas Cloud Experiment |
title_full |
Relationships between particles, cloud condensation nuclei and cloud droplet activation during the third Pallas Cloud Experiment |
title_fullStr |
Relationships between particles, cloud condensation nuclei and cloud droplet activation during the third Pallas Cloud Experiment |
title_full_unstemmed |
Relationships between particles, cloud condensation nuclei and cloud droplet activation during the third Pallas Cloud Experiment |
title_sort |
relationships between particles, cloud condensation nuclei and cloud droplet activation during the third pallas cloud experiment |
publishDate |
2018 |
url |
https://doi.org/10.5194/acp-12-11435-2012 https://www.atmos-chem-phys.net/12/11435/2012/ |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Northern Finland |
genre_facet |
Arctic Northern Finland |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-12-11435-2012 https://www.atmos-chem-phys.net/12/11435/2012/ |
op_doi |
https://doi.org/10.5194/acp-12-11435-2012 |
container_title |
Atmospheric Chemistry and Physics |
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12 |
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23 |
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11435 |
op_container_end_page |
11450 |
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1766343174540754944 |