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| Titel |
High temporal resolution estimates of columnar aerosol microphysical parameters from spectrum of aerosol optical depth by linear estimation: application to long-term AERONET and star-photometry measurements |
| VerfasserIn |
D. Pérez-Ramírez, I. Veselovskii, D. N. Whiteman, A. Suvorina, M. Korenskiy, A. Kolgotin, B. Holben, O. Dubovik, A. Siniuk, L. Alados-Arboledas |
| 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 ; 8, no. 8 ; Nr. 8, no. 8 (2015-08-05), S.3117-3133 |
| Datensatznummer |
250116519
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| Publikation (Nr.) |
 copernicus.org/amt-8-3117-2015.pdf |
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| Zusammenfassung |
| This work deals with the applicability of the linear estimation technique
(LE) to invert spectral measurements of aerosol optical depth (AOD) provided
by AERONET CIMEL sun photometers. The inversion of particle properties using
only direct-sun AODs allows the evaluation of parameters such as effective
radius (reff) and columnar volume aerosol content (V) with significantly
better temporal resolution than the operational AERONET algorithm which
requires both direct sun and sky radiance measurements. Sensitivity studies
performed demonstrate that the constraints on the range of the inversion are
very important to minimize the uncertainties, and therefore estimates of
reff can be obtained with uncertainties less than 30 % and of V with
uncertainties below 40 %. The LE technique is applied to data acquired at
five AERONET sites influenced by different aerosol types and the retrievals
are compared with the results of the operational AERONET code. Good
agreement between the two techniques is obtained when the fine mode
predominates, while for coarse mode cases the LE results systematically
underestimate both reff and V. The highest differences are found for
cases where no mode predominates. To minimize these biases, correction
functions are developed using the multi-year database of observations at
selected sites, where the AERONET retrieval is used as the reference. The
derived corrections are tested using data from 18 other AERONET stations
offering a range of aerosol types. After correction, the LE retrievals
provide better agreement with AERONET for all the sites considered. Finally,
the LE approach developed here is applied to AERONET and star-photometry
measurements in the city of Granada (Spain) to obtain day-to-night time
evolution of columnar aerosol microphysical properties. |
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