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| Titel |
Vertical profiles of lightning-produced NO2 enhancements in the upper troposphere observed by OSIRIS |
| VerfasserIn |
C. E. Sioris, C. A. McLinden, R. V. Martin, B. Sauvage, C. S. Haley, N. D. Lloyd, E. J. Llewellyn, P. F. Bernath, C. D. Boone, S. Brohede, C. T. McElroy |
| 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 ; 7, no. 16 ; Nr. 7, no. 16 (2007-08-21), S.4281-4294 |
| Datensatznummer |
250005169
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| Publikation (Nr.) |
 copernicus.org/acp-7-4281-2007.pdf |
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| Zusammenfassung |
| The purpose of this study is to perform a global search of the upper
troposphere (z≥10 km) for enhancements of nitrogen dioxide and
determine their sources. This is the first application of satellite-based
limb scattering to study upper tropospheric NO2. We have searched two
years (May 2003–May 2005) of OSIRIS (Optical Spectrograph and Infrared
Imager System) operational NO2 concentrations (version 2.3/2.4) to find
large enhancements in the observations by comparing with photochemical box
model calculations and by identifying local maxima in NO2 volume mixing
ratio. We find that lightning is the main production mechanism responsible
for the large enhancements in OSIRIS NO2 observations as expected.
Similar patterns in the abundances and spatial distribution of the NO2
enhancements are obtained by perturbing the lightning within the GEOS-Chem
3-dimensional chemical transport model. In most cases, the presence of
lightning is confirmed with coincident imagery from LIS (Lightning Imaging
Sensor) and the spatial extent of the NO2 enhancement is mapped using
nadir observations of tropospheric NO2 at high spatial resolution from
SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric
Chartography) and OMI (Ozone Monitoring Instrument). The combination of the
lightning and chemical sensors allows us to investigate globally the role of
lightning to the abundance of NO2 in the upper troposphere (UT).
Lightning contributes 60% of the tropical upper tropospheric NO2 in
GEOS-Chem simulations. The spatial and temporal distribution of NO2
enhancements from lightning (May 2003–May 2005) is investigated. The
enhancements generally occur at 12 to 13 km more frequently than at 10 to 11 km. This
is consistent with the notion that most of the NO2 is forming
and persisting near the cloud top altitude in the tropical upper
troposphere. The latitudinal distribution is mostly as expected. In general,
the thunderstorms exhibiting weaker vertical development (e.g. 11≤z≤13 km) extend latitudinally as far poleward as 45° but the
thunderstorms with stronger vertical development (z≥14 km) tend to be
located within 33° of the equator. There is also the expected
hemispheric asymmetry in the frequency of the NO2 enhancements, as most
were observed in the northern hemisphere for the period analyzed. |
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