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| Titel |
Retrieval of atmospheric profiles and cloud properties from IASI spectra using super-channels |
| VerfasserIn |
X. Liu, D. K. Zhou, A. M. Larar, W. L. Smith, P. Schluessel, S. M. Newman, J. P. Taylor, W. Wu |
| 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 ; 9, no. 23 ; Nr. 9, no. 23 (2009-12-03), S.9121-9142 |
| Datensatznummer |
250007781
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| Publikation (Nr.) |
 copernicus.org/acp-9-9121-2009.pdf |
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| Zusammenfassung |
| The Infrared Atmospheric Sounding Interferometer (IASI) is an ultra-spectral
satellite sensor with 8461 spectral channels. IASI spectra contain high
information content on atmospheric, cloud, and surface properties. The
instrument presents a challenge for using thousands of spectral channels in
a physical retrieval system or in a Numerical Weather Prediction (NWP) data
assimilation system. In this paper we describe a method of simultaneously
retrieving atmospheric temperature, moisture, and cloud properties using all
available IASI channels without sacrificing computational speed. The essence
of the method is to convert the IASI channel radiance spectra into
super-channels by an Empirical Orthogonal Function (EOF) transformation.
Studies show that about 100 super-channels are adequate to capture the
information content of the radiance spectra. A Principal Component-based
Radiative Transfer Model (PCRTM) is used to calculate both the super-channel
magnitudes and derivatives with respect to atmospheric profiles and other
properties. A physical retrieval algorithm then performs an inversion of
atmospheric, cloud, and surface properties in the super channel domain directly
therefore both reducing the computational need and preserving the
information content of the IASI measurements. While no large-scale
validation has been performed on any retrieval methodology presented in this
paper, comparisons of the retrieved atmospheric profiles, sea surface
temperatures, and surface emissivities with co-located ground- and aircraft-based
measurements over four days in Spring 2007 over the South-Central United
States indicate excellent agreement. |
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