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| Titel |
Mid-tropospheric δD observations from IASI/MetOp at high spatial and temporal resolution |
| VerfasserIn |
J.-L. Lacour, C. Risi, L. Clarisse, S. Bony, D. Hurtmans, C. Clerbaux, P.-F. Coheur |
| 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 ; 12, no. 22 ; Nr. 12, no. 22 (2012-11-16), S.10817-10832 |
| Datensatznummer |
250011600
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| Publikation (Nr.) |
 copernicus.org/acp-12-10817-2012.pdf |
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| Zusammenfassung |
| In this paper we retrieve atmospheric HDO,
H2O concentrations and their ratio δD from IASI radiances
spectra. Our method relies on an existing radiative transfer model
(Atmosphit) and an optimal estimation inversion scheme, but goes
further than our previous work by explicitly considering
correlations between the two species. A global HDO and H2O a priori profile together with
a covariance matrix were built from daily LMDz-iso model simulations of
HDO and H2O profiles over the whole globe and a whole year. The retrieval
parameters are described and characterized in terms of
errors. We show that IASI is mostly sensitive to
δD in the middle troposphere and allows
retrieving δD for an integrated
3–6 km column with an error of 38‰ on an
individual measurement basis. We examine the performance of the retrieval to capture the temporal (seasonal and
short-term) and spatial variations of δD
for one year of measurement at two dedicated sites
(Darwin and Izaña) and a latitudinal band from −60°
to 60° for a 15 day period in January. We report
a generally good agreement between IASI and the model and
indicate the capabilities of IASI to reproduce the large
scale variations of δD (seasonal cycle and
latitudinal gradient) with good accuracy. In particular, we
show that there is no systematic significant bias in the
retrieved δD values in comparison with the
model, and that the retrieved variability is similar to the
one in the model even though there are certain local differences. Moreover, the noticeable differences
between IASI and the model are briefly examined and
suggest modeling issues instead of retrieval
effects. Finally, the results further reveal the unprecedented capabilities
of IASI to capture short-term variations in
δD, highlighting the added value of
the sounder for monitoring hydrological processes. |
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