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| Titel |
Intercomparison of HONO SCDs and profiles from MAX-DOAS observations during the MAD-CAT campaign and comparison to chemical model simulations |
| VerfasserIn |
Yang Wang, Thomas Wagner, Pinhua Xie, Julia Remmers, Ang Li, Johannes Lampel, Udo Frieß, Enno Peters, Folkard Wittrock, Andreas Richter, Andreas Hilboll, Rainer Volkamer, Ivan Ortega, Francois Hendrick, Michel Van Roozendael, Jianzhong Ma, Junli Jin, Hang Su, Yafang Cheng |
| 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 |
250105211
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| Publikation (Nr.) |
 EGU/EGU2015-4674.pdf |
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| Zusammenfassung |
| In order to promote the development of the passive DOAS technique and to improve the
retrieval algorithms of trace gases and aerosols the Multi Axis DOAS – Comparison
campaign for Aerosols and Trace gases (MAD-CAT) was held at the Max Planck Institute for
Chemistry in Mainz, Germany from June to October 2013. MAX-DOAS (Multi-Axis
Differential Optical Absorption Spectroscopy) instruments of various designs recorded
UV-visible spectra of scattered sunlight at different elevation and azimuth angles. We present
intercomparison results for slant column densities (SCDs) of nitrous acid (HONO) retrieved
during this campaign by several research groups. Data analysis was performed in two steps,
starting with the preferred settings of the individual groups, followed by an analysis using
common retrieval settings. In general good agreement of the resulting HONO SCD sets was
found. Furthermore, we performed various sensitivity analyses to improve and evaluate the
uncertainties in the HONO SCD retrieval, such as the influence of the wavelength
dependence of the NO2 air mass factor, the selection of the wavelength interval of the
retrieval, the choice of the Fraunhofer reference spectrum, or the offset correction.
Finally we compared the results from different kinds of inversion algorithms for the
vertical profiles of trace gases and aerosols. The derived HONO profiles, VMR
near surface and tropospheric vertical column densities are compared with each
other and with the results of regional chemical model simulations. We found a high
HONO VMR near surface of about 200 ppt, which is much higher than the typical
daytime VMR of lower than 10 ppt at the early noon (around 9:30 local time),
probably indicating a strong source of HONO. The strong vertical gradient in the
profile of HONO VMR probably indicates the HONO source is close to the surface. |
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