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| Titel |
Water vapor isotopologue retrievals from high-resolution GOSAT shortwave infrared spectra |
| VerfasserIn |
C. Frankenberg, D. Wunch, G. Toon, C. Risi, R. Scheepmaker, J.-E. Lee, P. Wennberg, J. Worden |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 6, no. 2 ; Nr. 6, no. 2 (2013-02-07), S.263-274 |
| Datensatznummer |
250017388
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| Publikation (Nr.) |
 copernicus.org/amt-6-263-2013.pdf |
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| Zusammenfassung |
| Remote sensing of the isotopic composition of water vapor can provide
valuable information on the hydrological cycle. Here, we demonstrate the
feasibility of retrievals of the relative abundance of HDO (the HDO/H2O
ratio) from the Japanese GOSAT satellite. For this purpose, we use high
spectral resolution nadir radiances around 6400 cm−1
(1.56 μm) to retrieve vertical column amounts of H2O and HDO.
Retrievals of H2O correlate well with ECMWF (European Centre for
Medium-Range Weather Forecasts) integrated profiles (r2 = 0.96). Typical
precision errors in the retrieved column-averaged deuterium depletion
(δD) are 20–40‰. We compare δD against a TCCON
(Total Carbon Column Observing Network) ground-based station in Lamont,
Oklahoma. Using retrievals in very dry areas over Antarctica, we detect a
small systematic offset in retrieved H2O and HDO column amounts and take
this into account for a bias correction of δD. Monthly averages of
δD in the June 2009 to September 2011 time frame are well correlated
with TCCON (r2 = 0.79) and exhibit a slope of 0.98 (1.23 if not bias
corrected). We also compare seasonal averages on the global scale with
results from the SCIAMACHY instrument in the 2003–2005 time frame. Despite
the lack of temporal overlap, seasonal averages in general agree well, with
spatial correlations (r2) ranging from 0.62 in September through November
to 0.83 in June through August. However, we observe higher variability in
GOSAT δD, indicated by fitted slopes between 1.2 and 1.46. The
discrepancies are likely related to differences in vertical sensitivities but
warrant further validation of both GOSAT and SCIAMACHY and an extension of
the validation dataset. |
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