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| Titel |
Multiple wavelength retrieval of tropospheric aerosol optical properties from MAXDOAS measurements in Beijing |
| VerfasserIn |
K. Clémer, M. Roozendael, C. Fayt, F. Hendrick, C. Hermans, G. Pinardi, R. Spurr, P. Wang, M. Mazière |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 3, no. 4 ; Nr. 3, no. 4 (2010-07-08), S.863-878 |
| Datensatznummer |
250001206
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| Publikation (Nr.) |
 copernicus.org/amt-3-863-2010.pdf |
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| Zusammenfassung |
| We report on the retrieval of aerosol extinction profiles at four
wavelengths from ground-based multi-axis differential absorption
spectroscopy (MAXDOAS) measurements performed in Beijing, China.
Measurements were made over a 10-month time period (June 2008 to April 2009)
using a newly developed MAXDOAS instrument. A retrieval algorithm, based on
an on-line implementation of the radiative transfer code LIDORT and the
optimal estimation technique, has been designed to provide near real time
information on aerosol extinction vertical profiles. The algorithm was
applied to O4 measurements at four wavelengths (360, 477, 577, and 630 nm).
The total aerosol optical depths (AODs) calculated from the retrieved
profiles exhibit higher values in spring and summer and lower values in
autumn and winter. Comparison of the retrieved total AODs with values from a
co-located CIMEL sunphotometer revealed a good correlation. The best results
are obtained for the UV region with a correlation coefficient (R) of 0.91
and a slope of the linear regression fit of 1.1. At the longest wavelength,
R drops down to 0.67 and the slope increases to 1.5. The results confirm
that good quality O4 slant column measurements are essential for the
success of the retrievals. A method is presented to determine a correction
factor to account for systematic errors. It is demonstrated that the
algorithm is capable of reliably retrieving aerosol extinction profiles for
a wide range of atmospheric conditions (total AODs at 360 nm ranging from
about 0.1 to 3). The results open up new perspectives for the extension of
the algorithm for the near real time retrieval of trace gas vertical
profiles. |
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