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| Titel |
Retrieval of Aerosol Profiles using Multi Axis Differential Absorption Spectroscopy (MAX-DOAS) |
| VerfasserIn |
S. Yilmaz, U. Frieß, A. Apituley, G. de Leeuw, U. Platt |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026958
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| Zusammenfassung |
| Multi Axis Differential Absorption Spectroscopy (MAX-DOAS) is a well established
measurement technique to derive atmospheric trace gas profiles. Using MAX-DOAS
measurements of trace gases with a known vertical profile, like the oxygen-dimer O4, it is
possible to retrieve information on atmospheric aerosols. Based on the optimal estimation
method, we have developed an algorithm which fits simultaneously measured O4
optical densities at several wavelengths and elevation angles to values simulated by a
radiative transfer model. Retrieval parameters are aerosol extinction profile and optical
properties like single scattering albedo, phase function and Angström exponent. In the
scope of a joint research activity of the EU funded project EUSAAR (European
Supersites for Atmospheric Aerosol Research) we have developed a new kind of DOAS
instrument, which uses three miniature spectrometers to cover the near-ultraviolet to
visible wavelength range (290–790nm), enabling to capture all absorption bands
of the oxygen-dimer O4. Additionally, it is possible to point to any direction in
the sky with a 2D telescope unit which is connected to the spectrometers via fiber
optics.
In May 2008, an intercomparison campaign with established aerosol measurement techniques
took place in Cabauw/Netherlands, where simultaneous DOAS, LIDAR, Sun photometer and
Nephelometer measurements were performed. We present first results of selected days from
this period. The optical properties of aerosols retrieved by the DOAS measurement technique
show very promising qualitative agreement with the established measurement techniques
demonstrating the progress towards our goal of establishing the MAX-DOAS technique for
retrieving optical properties of atmospheric aerosols. Quantitative comparison is
ongoing. |
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