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| Titel |
Saharan dust infrared optical depth and altitude retrieved from AIRS: a focus over North Atlantic – comparison to MODIS and CALIPSO |
| VerfasserIn |
S. Peyridieu, A. Chédin, D. Tanré, V. Capelle, C. Pierangelo, N. Lamquin, R. Armante |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 4 ; Nr. 10, no. 4 (2010-02-19), S.1953-1967 |
| Datensatznummer |
250008127
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| Publikation (Nr.) |
 copernicus.org/acp-10-1953-2010.pdf |
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| Zusammenfassung |
| Monthly mean infrared (10 μm) dust layer aerosol
optical depth (AOD) and mean altitude are simultaneously
retrieved over the tropics (30° S–30° N)
from almost seven years of Atmospheric Infrared Sounder (AIRS)
observations covering the period January 2003 to September
2009. The method developed relies on the construction of
look-up-tables computed for a large selection of atmospheric
situations and follows two main steps: first, determination of
the observed atmospheric thermodynamic situation and, second,
determination of the dust properties. A very good agreement is
found between AIRS-retrieved AODs and visible optical depths
from the Moderate resolution Imaging Spectroradiometer
(MODIS/Aqua) during the main (summer) dust season, in
particular for three regions of the tropical North Atlantic
and one region of the north-western Indian Ocean. Outside
this season, differences are mostly due to the sensitivity of
MODIS to aerosol species other than dust and to the more
specific sensitivity of AIRS to the dust coarse mode.
AIRS-retrieved dust layer mean altitudes are compared to the
Cloud-Aerosol Lidar with Orthogonal Polarization
(CALIOP/CALIPSO) aerosol mean layer altitude for the period
June 2006 to June 2009. Results for a region of the north
tropical Atlantic downwind of the Sahara show a good agreement
between the two products (σ≈360 m).
Differences observed in the peak-to-trough seasonal amplitude,
smaller from AIRS, are principally attributed to the large
difference in spatial sampling of the two instruments. They
also come from the intrinsic limit in sensitivity of the
passive infrared sounders for low altitudes. These results
demonstrate the capability of high resolution infrared
sounders to measure not only dust aerosol AOD but also the
mean dust layer altitude. |
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