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| Titel |
Vertical profiling of aerosol particles and trace gases over the central Arctic Ocean during summer |
| VerfasserIn |
P. Kupiszewski, C. Leck, M. Tjernström, S. Sjogren, J. Sedlar, M. Graus, M. Müller, B. Brooks, E. Swietlicki, S. Norris, A. Hansel |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 24 ; Nr. 13, no. 24 (2013-12-19), S.12405-12431 |
| Datensatznummer |
250085893
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| Publikation (Nr.) |
 copernicus.org/acp-13-12405-2013.pdf |
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| Zusammenfassung |
Unique measurements of vertical size-resolved aerosol particle
concentrations, trace gas concentrations and meteorological data were
obtained during the Arctic Summer Cloud Ocean Study (ASCOS,
www.ascos.se), an International Polar Year project aimed at
establishing the processes responsible for formation and evolution of
low-level clouds over the high Arctic summer pack ice. The experiment was
conducted from on board the Swedish icebreaker Oden, and provided
both ship- and helicopter-based measurements. This study focuses on the
vertical helicopter profiles and onboard measurements obtained during
a three-week period when Oden was anchored to a drifting ice floe,
and sheds light on the characteristics of Arctic aerosol particles and their
distribution throughout the lower atmosphere.
Distinct differences in aerosol particle characteristics within defined
atmospheric layers are identified. Within the lowermost couple hundred
metres, transport from the marginal ice zone (MIZ), condensational growth and
cloud processing develop the aerosol population. During two of the four
representative periods defined in this study, such influence is shown. At
altitudes above about 1 km, long-range transport occurs frequently.
However, only infrequently does large-scale subsidence descend such air
masses to become entrained into the mixed layer in the high Arctic, and
therefore long-range transport plumes are unlikely to directly influence
low-level stratiform cloud formation. Nonetheless, such plumes can influence
the radiative balance of the planetary boundary layer (PBL) by influencing
formation and evolution of higher clouds, as well as through precipitation
transport of particles downwards. New particle formation was occasionally
observed, particularly in the near-surface layer. We hypothesize that the
origin of these ultrafine particles could be in biological processes, both
primary and secondary, within the open leads between the pack ice and/or
along the MIZ. In general, local sources, in combination with upstream
boundary-layer transport of precursor gases from the MIZ, are considered to
constitute the origin of cloud condensation nuclei (CCN) particles and thus
be of importance for the formation of interior Arctic low-level clouds during
summer, and subsequently, through cloud influences, for the melting
and freezing of sea ice. |
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