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| Titel |
A posteriori calculation of δ18O and δD in atmospheric water vapour from ground-based near-infrared FTIR retrievals of H216O, H218O, and HD16O |
| VerfasserIn |
N. V. Rokotyan, V. I. Zakharov, K. G. Gribanov, M. Schneider, F.-M. Bréon, J. Jouzel, R. Imasu, M. Werner, M. Butzin, C. Petri, T. Warneke, J. Notholt |
| 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 ; 7, no. 8 ; Nr. 7, no. 8 (2014-08-18), S.2567-2580 |
| Datensatznummer |
250115874
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| Publikation (Nr.) |
 copernicus.org/amt-7-2567-2014.pdf |
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| Zusammenfassung |
This paper investigates the scientific value of retrieving H218O
and HDO columns in addition to H216O columns from high-resolution ground-based near-infrared spectra. We present a set of refined
H216O, H218O, and HDO spectral windows. The
retrieved H216O, H218O, and HDO columns are used
for an a posteriori calculation of columnar δD and
δ18O. We estimate the uncertainties for the so-calculated
columnar δD and δ18O values. These estimations include
uncertainties due to the measurement noise, errors in the a priori data, and
uncertainties in spectroscopic parameters. Time series of δ18O
obtained from ground-based FTIR (Fourier transform infrared) spectra are presented for the first time.
For our study we use a full physics isotopic general circulation model
(ECHAM5-wiso). We show that the full physics simulation of HDO and
H218O can already be reasonably predicted from the
H216O columns by a simple linear regression model (scatter values
between full physics and linear regression simulations are 35 and
4‰ for HDO and H218O, respectively). We document
that the columnar δD and δ18O values as calculated a
posteriori from the retrievals of H216O, H218O, and
HDO show a better agreement with the ECHAM5-wiso simulation than the
δD and δ18O values as calculated from the
H216O retrievals and the simple linear regression model. This
suggests that the H218O and HDO column retrievals add
complementary information to the H216O retrievals. However, these
data have to be used carefully, because of the different vertical sensitivity
of the H216O, H218O, and HDO columnar
retrievals. Furthermore, we have to note that the retrievals use reanalysis
humidity profiles as a priori input and the results are thus not independent
of the reanalysis data. |
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