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| Titel |
Denitrification and polar stratospheric cloud formation during the Arctic winter 2009/2010 |
| VerfasserIn |
F. Khosrawi, J. Urban, M. C. Pitts, P. Voelger, P. Achtert, M. Kaphlanov, M. L. Santee, G. L. Manney, D. Murtagh, K.-H. Fricke |
| 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 ; 11, no. 16 ; Nr. 11, no. 16 (2011-08-19), S.8471-8487 |
| Datensatznummer |
250010016
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| Publikation (Nr.) |
 copernicus.org/acp-11-8471-2011.pdf |
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| Zusammenfassung |
| The sedimentation of HNO3 containing Polar
Stratospheric Cloud (PSC) particles leads to a permanent
removal of HNO3 and thus to a denitrification of the
stratosphere, an effect which plays an important role in
stratospheric ozone depletion. The polar vortex in the Arctic
winter 2009/2010 was very cold and stable between end of
December and end of January. Strong denitrification between
475 to 525 K was
observed in the Arctic in mid of January by the Odin Sub
Millimetre Radiometer (Odin/SMR). This was the strongest
denitrification that had been observed in the entire Odin/SMR
measuring period (2001–2010). Lidar measurements of PSCs were
performed in the area of Kiruna, Northern Sweden with the IRF
(Institutet för Rymdfysik) lidar and with the Esrange lidar
in January 2010. The measurements show that PSCs were present
over the area of Kiruna during the entire period of
observations. The formation of PSCs during the Arctic winter
2009/2010 is investigated using a microphysical box model. Box
model simulations are performed along air parcel trajectories
calculated six days backward according to the PSC measurements
with the ground-based lidar in the Kiruna area. From the
temperature history of the backward trajectories and the box model
simulations we find two PSC regions, one over Kiruna according
to the measurements made in Kiruna and one north of
Scandinavia which is much colder, reaching also temperatures
below Tice. Using the box model simulations along
backward trajectories together with the observations of
Odin/SMR, Aura/MLS (Microwave Limb Sounder), CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder
Satellite Observations) and the ground-based lidar we
investigate how and by which type of PSC particles the
denitrification that was observed during the Arctic winter
2009/2010 was caused. From our analysis we find that due to an
unusually strong synoptic cooling event in mid January, ice
particle formation on NAT may be a possible formation mechanism during that
particular winter that may have caused the denitrification observed in mid
January. In contrast, the denitrification that was observed in the beginning
of January could have been caused by the sedimentation of NAT particles that
formed on mountain wave ice clouds. |
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