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Titel |
Intercomparison of integrated IASI and AATSR calibrated radiances at 11 and 12 μm |
VerfasserIn |
S. M. Illingworth, J. J. Remedios, R. J. Parker |
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. 18 ; Nr. 9, no. 18 (2009-09-15), S.6677-6683 |
Datensatznummer |
250007625
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Publikation (Nr.) |
copernicus.org/acp-9-6677-2009.pdf |
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Zusammenfassung |
The mission objectives of the Infrared Atmospheric Sounding Interferometer
(IASI) are driven by the needs of the Numerical Weather Prediction (NWP) and
climate monitoring communities. These objectives rely upon the IASI
instrument being able to measure top of atmosphere radiances accurately. This
paper presents a technique and first results for the validation of the
radiometric calibration of radiances for IASI, using a cross-calibration with
the Advanced Along Track Scanning Radiometer (AATSR). The AATSR is able to
measure Brightness Temperature (BT) to an accuracy of 30 mK, and by applying
the AATSR spectral filter functions to the IASI measured radiances we are able
to compare AATSR and IASI Brightness Temperatures. By choosing coincident
data points that are over the sea and in clear sky conditions, a threshold of
homogeneity is derived. It is found that in these homogenous conditions, the
IASI BTs agree with those measured by the AATSR to within 0.3 K, with an
uncertainty of order 0.1 K. The agreement is particularly good at
11 μm where the difference is less than 0.1 K. These first results
indicate that IASI is meeting its target objective of 0.5 K accuracy. It is
believed that a refinement of the AATSR spectral filter functions will
hopefully permit a tighter error constraint on the quality of the IASI data
and hence further assessment of the climate quality of the radiances. |
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