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| Titel |
Estimate of bias in Aura TES HDO/H2O profiles from comparison of TES and in situ HDO/H2O measurements at the Mauna Loa observatory |
| VerfasserIn |
J. Worden, D. Noone, J. Galewsky, A. Bailey, K. Bowman, D. Brown, J. Hurley, S. Kulawik, J. Lee, M. Strong |
| 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. 9 ; Nr. 11, no. 9 (2011-05-12), S.4491-4503 |
| Datensatznummer |
250009715
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| Publikation (Nr.) |
 copernicus.org/acp-11-4491-2011.pdf |
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| Zusammenfassung |
| The Aura satellite Tropospheric Emission Spectrometer
(TES) instrument is capable of measuring the HDO/H2O ratio in the lower
troposphere using thermal infrared radiances between 1200 and 1350 cm−1. However, direct validation of these measurements is challenging
due to a lack of in situ measured vertical profiles of the HDO/H2O
ratio that are spatially and temporally co-located with the TES
observations. From 11 October through 5 November 2008, we undertook a
campaign to measure HDO and H2O at the Mauna Loa observatory in Hawaii
for comparison with TES observations. The Mauna Loa observatory is situated
at 3.1 km above sea level or approximately 680 hPa, which is approximately
the altitude where the TES HDO/H2O observations show the most
sensitivity. Another advantage of comparing in situ data from this site to
estimates derived from thermal IR radiances is that the volcanic rock is
heated by sunlight during the day, thus providing significant thermal
contrast between the surface and atmosphere; this thermal contrast increases
the sensitivity to near surface estimates of tropospheric trace gases. The
objective of this inter-comparison is to better characterize a bias in the
TES HDO data, which had been previously estimated to be approximately 5 %
too high for a column integrated value between 850 hPa and 500 hPa. We
estimate that the TES HDO profiles should be corrected downwards by
approximately 4.8 % and 6.3 % for Versions 3 and 4 of the data
respectively. These corrections must account for the vertical sensitivity of
the TES HDO estimates. We estimate that the precision of this bias
correction is approximately 1.9 %. The accuracy is driven by the
corrections applied to the in situ HDO and H2O measurements using flask data
taken during the inter-comparison campaign and is estimated to be less than
1 %. Future comparisons of TES data to accurate vertical profiles of in situ
measurements are needed to refine this bias estimate. |
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