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Titel |
Nitric Acid Trihydrate (NAT) formation at low NAT supersaturation in Polar Stratospheric Clouds (PSCs) |
VerfasserIn |
C. Voigt, H. Schlager, B. P. Luo, A. Dörnbrack, A. Roiger, P. Stock, J. Curtius, H. Vössing, S. Borrmann, S. Davies, P. Konopka, C. Schiller, G. Shur, T. Peter |
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 ; 5, no. 5 ; Nr. 5, no. 5 (2005-06-08), S.1371-1380 |
Datensatznummer |
250002815
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Publikation (Nr.) |
copernicus.org/acp-5-1371-2005.pdf |
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Zusammenfassung |
A PSC was detected on 6 February 2003 in the Arctic stratosphere
by in-situ measurements onboard the high-altitude research
aircraft Geophysica. Low number densities
(~10-4cm-3) of small nitric acid (HNO3)
containing particles (d<6µm) were observed at altitudes
between 18 and 20km. Provided the temperatures remain below the
NAT equilibrium temperature TNAT, these NAT particles
have the potential to grow further and to remove HNO3 from
the stratosphere, thereby enhancing polar ozone loss.
Interestingly, the NAT particles formed in less than a day at
temperatures just slightly below TNAT
(T>TNAT-3.1K). This unique measurement of PSC
formation at extremely low NAT saturation ratios
(SNAT≤10) constrains current NAT nucleation
theories. We suggest, that the NAT particles have formed
heterogeneously, but for certain not on ice. Conversely,
meteoritic particles may be favorable candidates for triggering
NAT nucleation at the observed low number densities. |
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