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| Titel |
Retrieval of ammonia from ground-based FTIR solar spectra |
| VerfasserIn |
E. Dammers, C. Vigouroux, M. Palm, E. Mahieu, T. Warneke, D. Smale, B. Langerock, B. Franco, M. Damme, M. Schaap, J. Notholt, J. W. Erisman |
| 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 ; 15, no. 22 ; Nr. 15, no. 22 (2015-11-18), S.12789-12803 |
| Datensatznummer |
250120168
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| Publikation (Nr.) |
 copernicus.org/acp-15-12789-2015.pdf |
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| Zusammenfassung |
| We present a retrieval method for ammonia (NH3) total
columns from ground-based Fourier transform infrared (FTIR) observations.
Observations from Bremen (53.10° N, 8.85° E), Lauder (45.04° S, 169.68° E), Réunion
(20.9° S, 55.50° E) and Jungfraujoch (46.55° N, 7.98° E) were used to illustrate the
capabilities of the method. NH3 mean total columns ranging 3
orders of magnitude were obtained, with higher values at Bremen (mean of
13.47 × 1015 molecules cm−2) and lower values at Jungfraujoch (mean of
0.18 × 1015 molecules cm−2). In conditions with high surface concentrations
of ammonia, as in Bremen, it is possible to retrieve information on the
vertical gradient, as two layers can be distinguished. The retrieval there is
most sensitive to ammonia in the planetary boundary layer, where the trace
gas concentration is highest. For conditions with low concentrations, only
the total column can be retrieved. Combining the systematic and random
errors we have a mean total error of 26 % for all spectra measured at
Bremen (number of spectra (N) = 554), 30 % for all spectra from Lauder
(N = 2412), 25 % for spectra from Réunion (N = 1262) and 34 % for
spectra measured at Jungfraujoch (N = 2702). The error is dominated by the
systematic uncertainties in the spectroscopy parameters. Station-specific
seasonal cycles were found to be consistent with known seasonal cycles of
the dominant ammonia sources in the station surroundings. The developed
retrieval methodology from FTIR instruments provides a new way of obtaining
highly time-resolved measurements of ammonia burdens. FTIR-NH3 observations will be useful for understanding the dynamics of ammonia
concentrations in the atmosphere and for satellite and model validation. It
will also provide additional information to constrain the global ammonia
budget. |
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