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| Titel |
Comparisons between ground-based FTIR and MIPAS N2O and HNO3 profiles before and after assimilation in BASCOE |
| VerfasserIn |
C. Vigouroux, M. Mazière, Q. Errera, S. Chabrillat, E. Mahieu, P. Duchatelet, S. Wood, D. Smale, S. Mikuteit, T. Blumenstock, F. Hase, N. Jones |
| 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 ; 7, no. 2 ; Nr. 7, no. 2 (2007-01-23), S.377-396 |
| Datensatznummer |
250004464
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| Publikation (Nr.) |
 copernicus.org/acp-7-377-2007.pdf |
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| Zusammenfassung |
| Within the framework of the Network for Detection of Atmospheric Composition
Change (NDACC), regular ground-based Fourier transform infrared (FTIR)
measurements of many species are performed at several locations. Inversion
schemes provide vertical profile information and characterization of the
retrieved products which are therefore relevant for contributing to the
validation of MIPAS profiles in the stratosphere and upper troposphere.
We have focused on the species HNO3 and N2O at 5
NDACC-sites distributed in both hemispheres, i.e., Jungfraujoch
(46.5° N) and Kiruna (68° N) for the northern hemisphere, and
Wollongong (34° S), Lauder (45° S) and Arrival Heights
(78° S) for the southern hemisphere. These ground-based
data have been compared with MIPAS offline profiles (v4.61) for the year
2003, collocated within 1000 km around the stations, in the lower to middle
stratosphere. To get around the spatial collocation problem, comparisons have
also been made between the same ground-based FTIR data and the corresponding
profiles resulting from the stratospheric 4D-VAR data assimilation system
BASCOE constrained by MIPAS data. This paper discusses the results of the comparisons and the
usefullness of using BASCOE profiles as proxies for MIPAS data. It shows good
agreement between MIPAS and FTIR N2O partial columns: the biases are
below 5% for all the stations and the standard deviations are below 7% for
the three mid-latitude stations, and below 10% for the high latitude ones.
The comparisons with BASCOE partial columns give standard deviations below
4% for the mid-latitude stations to less than 8% for the high latitude
ones. After making some corrections to take into account the known bias due
to the use of different spectroscopic parameters, the comparisons of
HNO3 partial columns show biases below 3% and standard deviations
below 15% for all the stations except Arrival Heights (bias of 5%, standard
deviation of 21%). The results for this species, which has a larger spatial
variability, highlight the necessity of defining appropriate collocation
criteria and of accounting for the spread of the observed airmasses. BASCOE
appears to have more deficiencies in producing proxies of MIPAS HNO3
profiles compared to N2O, but the obtained standard deviation of less
than 10% between BASCOE and FTIR is reasonable. Similar results on profiles
comparisons are also shown in the paper, in addition to partial column ones. |
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