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| Titel |
First detection of ammonia (NH3) in the upper troposphere |
| VerfasserIn |
Michael Höpfner, Rainer Volkamer, Udo Grabowski, Michel Grutter de la Mora, Johannes Orphal, Gabriele Stiller, Thomas von Clarmann |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250128865
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| Publikation (Nr.) |
 EGU/EGU2016-8897.pdf |
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| Zusammenfassung |
| Ammonia (NH3) is the major alkaline trace gas in the troposphere. Neutralization of
atmospheric acids, like HNO3 and H2SO4, leads to formation of ammonium nitrate and
ammonium sulfate aerosols. Further, there are indications that NH3 may enhance nucleation
of sulfuric acid aerosols by stabilization of sulfuric acid clusters. By far the largest source of
ammonia is agricultural food production. Major global emissions are located in
S-E Asia as e.g. shown by satellite nadir observations. Besides its importance with
respect to air quality issues, an increase of ammonia emissions in the 21st century
might lead to a significant climate radiative impact through aerosol formation. In
spite of its significance, there is a lack of observational information on the global
distribution of NH3 in the mid- and upper troposphere. Observational evidence, however,
would be important for testing e.g. model results on the fate of ammonia from its
source regions on ground to altitudes up to the tropopause. In this contribution
we will show, to our knowledge, the first unequivocal detection of ammonia in
the upper troposphere. This result has been achieved through analysis of infrared
limb-emission observations performed with the MIPAS (Michelson Interferometer for
Passive Atmospheric Sounding) instrument on board the Envisat satellite from
2002-2012. On a global scale, enhanced values of ammonia have been measured in the
upper tropospheric region influenced by the Asian monsoon. We will present a
quantitative analysis of the retrieved concentrations of NH3 including an error assessment
and further retrieval diagnostics. The results will be discussed with respect to the
variability of NH3 locally within the Asian monsoon region’s upper troposphere and at
different years. Further, we will show comparisons between global distributions of
NH3 from published model simulations and our observational dataset from MIPAS. |
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