| Title: | Regional new particle formation as modulators of cloud condensation nuclei and cloud droplet number in the eastern Mediterranean |
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| Authors: | ID Kalkavouras, Panayiotis (Author)
ID Bougiatioti, Aikaterini (Author)
ID Kalivitis, Nikos (Author)
ID Stavroulas, Iasonas (Author)
ID Tombrou, Maria (Author)
ID Nenes, Athanasios (Author)
ID Mihalopoulos, Nikolaos (Author) |
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| Files: |  acp-19-6185-2019.pdf (3,07 MB)
MD5: 2D45D5404C7E0EE316AFF161E29D56E3
 https://acp.copernicus.org/articles/19/6185/2019/acp-19-6185-2019.pdf
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| Language: | English |
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| Work type: | Unknown |
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| Typology: | 1.01 - Original Scientific Article |
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| Organization: | UNG - University of Nova Gorica
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| Abstract: | A significant fraction of atmospheric particles that serve as cloud
condensation nuclei (CCN) are thought to originate from the condensational
growth of new particle formation (NPF) from the gas phase. Here, 7 years of
continuous aerosol and meteorological measurements (June 2008 to May 2015)
at a remote background site of the eastern Mediterranean were recorded and
analyzed to assess the impact of NPF (of 162 episodes identified) on CCN and
cloud droplet number concentration (CDNC) formation in the region. A new
metric is introduced to quantitatively determine the initiation and duration
of the influence of NPF on the CCN spectrum. NPF days were found to increase
CCN concentrations (from 0.10 % to 1.00 % supersaturation) between 29 %
and 77 %. Enhanced CCN concentrations from NPF are mostly observed, as
expected, under low preexisting particle concentrations and occur in the
afternoon, relatively later in the winter and autumn than in the summer.
Potential impacts of NPF on cloud formation were quantified by introducing
the observed aerosol size distributions and chemical composition into an
established cloud droplet parameterization. We find that the
supersaturations that develop are very low (ranging between 0.03 % and
0.27 %) for typical boundary layer dynamics (σw
∼0.3 m s−1) and NPF is found to enhance CDNC by a modest
13 %. This considerable contrast between CCN and CDNC response is in part
from the different supersaturation levels considered, but also because
supersaturation drops from increasing CCN because of water vapor competition
effects during the process of droplet formation. The low cloud
supersaturation further delays the appearance of NPF impacts on CDNC to
clouds formed in the late evening and nighttime – which has important
implications for the extent and types of indirect effects induced by NPF
events. An analysis based on CCN concentrations using prescribed
supersaturation can provide very different, even misleading, conclusions and
should therefore be avoided. The proposed approach here offers a simple, yet
highly effective way for a more realistic impact assessment of NPF events on
cloud formation. |
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| Keywords: | regional NPF, CCN, cloud droplets, Eastern Mediterranean, regional background |
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| Publication date: | 01.01.2019 |
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| Year of publishing: | 2019 |
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| Number of pages: | str. 6185-6203 |
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| Numbering: | Vol. 19, issue 9 |
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| PID: | 20.500.12556/RUNG-9063  |
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| COBISS.SI-ID: | 195134723 |
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| UDC: | 53 |
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| ISSN on article: | 1680-7316 |
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| eISSN: | 1680-7324 |
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| DOI: | 10.5194/acp-19-6185-2019 |
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| NUK URN: | URN:SI:UNG:REP:YXMXBW9H |
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| Publication date in RUNG: | 13.05.2024 |
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| Views: | 983 |
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| Downloads: | 5 |
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