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Titel |
H2O and δD profiles remotely-sensed from ground in different spectral infrared regions |
VerfasserIn |
M. Schneider, G. C. Toon, J.-F. Blavier, F. Hase, T. Leblanc |
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 ; 3, no. 6 ; Nr. 3, no. 6 (2010-11-22), S.1599-1613 |
Datensatznummer |
250001363
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Publikation (Nr.) |
copernicus.org/amt-3-1599-2010.pdf |
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Zusammenfassung |
We present ground-based FTIR (Fourier Transform Infrared) water vapour
analyses performed in four different spectral regions: 790–880,
1090–1330, 2650–3180, and 4560–4710 cm−1. All four regions
allow the retrieval of lower, middle, and upper tropospheric water vapour
amounts with a vertical resolution of about 3, 6, and 10 km,
respectively. In addition the analyses at 1090–1330 and
2650–3180 cm−1 allow the retrieval of lower and middle/upper
tropospheric δD values with vertical resolutions of 3 and 10 km,
respectively. A theoretical and empirical error assessment – taking
coincident Vaisala RS92 radiosonde measurements as a reference – suggests
that the H2O data retrieved at high wavenumbers are slightly more precise
than those retrieved at low wavenumbers. We deduce an H2O profile
precision and accuracy of generally better than 20% except for the low
wavenumber retrieval at 790–880 cm−1, where the assessed upper
precision limit of middle/upper tropospheric H2O is 35%. The scatter
between the H2O profiles produced by the four different retrievals is
generally below 20% and the bias below 10%, except for the boundary
layer, where it can reach 24%. These values well confirm the theoretical
and empirical error assessment and are rather small compared to the huge
tropospheric H2O variability of about one order of magnitude thereby
demonstrating the large consistency between the different H2O profile
retrievals. By comparing the two δD profile versions we deduce a
precision of about 8 and 17‰ for the lower and middle/upper
troposphere, respectively. However, at the same time we observe a systematic
difference between the two retrievals of up to 40‰ in the middle/upper troposphere which is a
large value compared to the typical tropospheric δD variability of
only 80‰. |
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