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| Titel |
Azimuthal variability of trace gases and aerosols measured during the MADCAT campaign in summer 2013 in Mainz, Germany |
| VerfasserIn |
Julia Remmers, Thomas Wagner |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105489
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| Publikation (Nr.) |
 EGU/EGU2015-5018.pdf |
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| Zusammenfassung |
| With the MAX-DOAS technique it is possible to retrieve vertical profiles of trace gases and
aerosols in the lower troposphere. Often these instruments monitor the atmosphere in one
azimuthal direction only. Therefore horizontal variability is not resolved. Especially the
comparison to satellite data close to strong emission sources (one main application of
MAX-DOAS) is possibly biased.
MADCAT (Multi-Axis DOAS Comparison campaign for Aerosols and Trace gases) took
place in summer 2013 in Mainz, a city in the Rhine-Main region close to Frankfurt, with high
population density and many industrial complexes.
The main focus of this campaign was on the comparison of the results from the different
instruments. Therefore 16 MAX-DOAS instruments from 10 different institutes were
operated on the roof of the MPI for Chemistry. In standard operation mode, vertical scans at
one or several selected azimuth viewing direction were performed. In addition, 6
instruments scanned the sky also in azimuth direction every two hours. These scans were
performed under a low elevation angle (2°) to capture the pollution close to the
ground.
A comparison of the trace gas columns derived from these instruments will be shown for
NO2 and O4, the latter is used to retrieve information about aerosols.
The observed variation for different azimuth angles does not only reflect a gradient in the
trace gas, but also differences in the light path length, which is affected by sun and viewing
geometry as well as aerosols. To distinguish between the different effects comparisons with
radiative transfer models are performed.
The results of the azimuth scans are also compared to car-DOAS measurements around
Mainz, which were conducted at least twice a day. |
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