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Titel |
Kalman filter physical retrieval of surface emissivity and temperature from SEVIRI infrared channels: a validation and intercomparison study |
VerfasserIn |
G. Masiello, C. Serio, S. Venafra, G. Liuzzi, F. Göttsche, I. F. Trigo, P. Watts |
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. 7 ; Nr. 8, no. 7 (2015-07-29), S.2981-2997 |
Datensatznummer |
250116492
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Publikation (Nr.) |
copernicus.org/amt-8-2981-2015.pdf |
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Zusammenfassung |
A Kalman filter-based approach for the physical retrieval of surface
temperature and emissivity from SEVIRI (Spinning Enhanced Visible and
Infrared Imager) infrared observations has been developed and validated
against in situ and satellite observations. Validation for land has been
provided based on in situ observations from the two permanent stations at
Evora and Gobabeb operated by Karlsruhe Institute of Technology (KIT) within
the framework of EUMETSAT's Satellite Application Facility on Land Surface
Analysis (LSA SAF). Sea surface retrievals have been intercompared on a broad
spatial scale with equivalent satellite products (MODIS, Moderate
Resolution Imaging Spectroradiometer, and AVHRR, Advanced Very High
Resolution Radiometer) and ECMWF (European Centre for Medium-Range Weather
Forecasts) analyses. For surface temperature, the Kalman filter yields a root
mean square accuracy of ≈ ±1.5 °C for the two land sites
considered and ≈ ±1.0 °C for the sea. Comparisons with
polar satellite instruments over the sea surface show nearly zero temperature
bias. Over the land surface the retrieved emissivity follows the seasonal
vegetation cycle and permits identification of desert sand regions using the
SEVIRI channel at 8.7 μm due to the strong quartz reststrahlen bands
around 8–9 μm. Considering the two validation stations, we have found
that emissivity retrieved in SEVIRI channel 10.8 μm over the gravel
plains of the Namibian desert is in excellent agreement with in situ
observations. Over Evora, the seasonal variation of emissivity with
vegetation is successfully retrieved and yields emissivity values for green
and dry vegetation that are in good agreement with spectral library data. The
algorithm has been applied to the SEVIRI full disk, and emissivity maps on
that global scale have been physically retrieved for the first time. |
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