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| Titel |
Nitric acid in the stratosphere based on Odin observations from 2001 to 2009 – Part 1: A global climatology |
| VerfasserIn |
J. Urban, M. Pommier, D. P. Murtagh, M. L. Santee, Y. J. Orsolini |
| 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 ; 9, no. 18 ; Nr. 9, no. 18 (2009-09-23), S.7031-7044 |
| Datensatznummer |
250007645
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| Publikation (Nr.) |
 copernicus.org/acp-9-7031-2009.pdf |
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| Zusammenfassung |
| The Sub-Millimetre Radiometer (SMR) on board the Odin satellite,
launched in February 2001, observes thermal emissions of
stratospheric nitric acid (HNO3) originating from the Earth limb
in a band centred at 544.6 GHz. Height-resolved measurements of the
global distribution of nitric acid in the stratosphere were
performed approximately on two observation days per week. An HNO3
climatology based on more than 7 years of observations from August
2001 to April 2009 covering the vertical range between typically
~19 and 45 km (~1.5–60 hPa or ~500–1800 K in
terms of potential temperature) was created. The study highlights
the spatial and seasonal variation of nitric acid in the
stratosphere, characterised by a pronounced seasonal cycle at middle
and high latitudes with maxima during late fall and minima during
spring, strong denitrification in the lower stratosphere of the
Antarctic polar vortex during winter (the irreversible removal of
NOy by the sedimentation of cloud particles containing
HNO3), as well as large quantities of HNO3 formed every winter
at high-latitudes in the middle and upper stratosphere. A strong
inter-annual variability is observed in particular at high
latitudes. A comparison with a stratospheric HNO3 climatology,
based on over 7 years of UARS/MLS (Upper Atmosphere Research
Satellite/Microwave Limb Sounder) measurements from the 1990s,
shows good consistency and agreement of the main morphological
features in the potential temperature range ~465 to
~960 K, if the different characteristics of the data sets such
as the better altitude resolution of Odin/SMR as well as the
slightly different altitude ranges are considered. Odin/SMR reaches
higher up and UARS/MLS lower down in the stratosphere. An overview
from 1991 to 2009 of stratospheric nitric acid is provided (with a
short gap between 1998 and 2001), if the global measurements of both
experiments are taken together. |
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