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| Titel |
Observation of clouds with an airborne DOAS instrument |
| VerfasserIn |
K.-P. Heue, C. Brenninkmeijer, D. Walter, T. Wagner, A. Zahn, T. Deutschmann, U. Platt |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250062833
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| Zusammenfassung |
| We report on observations of clouds with the CARIBIC (Civil Aircraft for Regular
Investigation of the atmosphere Based on an Instrument Container) using a DOAS
(Differential Optical Absorption Spectroscopy) instrument. The CARIBIC container is
regularly installed on a Lufthansa Airbus retrofitted with a three probe inlet (water,
aerosols and trace gases). The inlet also contains three small telescopes for the DOAS
instrument observing the column densities of oxygen dimers (O4) and additional trace
gases like NO2, HCHO or HONO. During frequent traverses of smaller clouds
enhancements of O4 are seen; however, the focus of the presentation will be on a cloud
event over the Caribbean. During one flight from Frankfurt to Caracas (Venezuela)
when the CARIBIC airbus penetrated a large convective cloud over the Caribbean
Sea; at this occasion the DOAS instrument observed strongly enhanced column
densities of O4 associated with a strong increase in the Ring effect (filling in of the
Fraunhofer lines caused by elastic scattering). At the same time the in situ cloud water
instrument measured a strong enhancement of cloud water. The observations are
compared with results of a 3-D Monte Carlo Radiative transfer Model to estimate
the cloud optical thickness (- 160) and the cloud top height (15 km). The high
optical density of the cloud enhanced multiple scattering and thereby the light path
was extended up to about 100 km inside the cloud. Thereby not only the cloud
optical properties can be estimated but also the trace gas concentration inside the
cloud. |
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