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| Titel |
The use of IASI data to identify systematic errors in the ECMWF forecasts of temperature in the upper stratosphere |
| VerfasserIn |
G. Masiello, M. Matricardi, C. Serio |
| 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. 3 ; Nr. 11, no. 3 (2011-02-04), S.1009-1021 |
| Datensatznummer |
250009288
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| Publikation (Nr.) |
 copernicus.org/acp-11-1009-2011.pdf |
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| Zusammenfassung |
| Since data from the Infrared Atmospheric Sounding Interferometer
(IASI) became available in 2007, a number of papers have appeared in
the literature which have reported relatively large discrepancies
between IASI spectra and forward calculations in the centre of the
CO2 Q-branch at 667 cm−1. In this paper we show that these
discrepancies are primarily due to errors in the temperature
profiles used in the forward calculations. In particular, we have
used forecasts of temperature profiles from the European Centre for Medium-Range
Weather Forecasts (ECMWF) to demonstrate that, for the case
study considered in this paper, these profiles are affected by
systematic errors of the order of ≈10 K at the level of the
stratopause. To derive the magnitude and the spatial location of the
systematic errors in the temperature profile, we have carried out
forward/inverse calculations for a number of clear-sky, daytime,
IASI tropical soundings over the sea. The forward calculations have
been performed using atmospheric state vectors which have been
obtained either from the direct inversion of the IASI radiances or
from space-time co-located profiles derived from radiosonde
observations and from the ECMWF model. To rule out any effect due to
the accuracy of the forward model, we have performed the forward
calculations using two independent models. The sensitivity of the
temperature biases to the variability of the CO2 profile and to
spectroscopy errors has also been studied. |
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