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Titel |
Extending the satellite data record of tropospheric ozone profiles from Aura-TES to MetOp-IASI: characterisation of optimal estimation retrievals |
VerfasserIn |
H. Oetjen, V. H. Payne, S. S. Kulawik, A. Eldering, J. Worden, D. P. Edwards, G. L. Francis, H. M. Worden, C. Clerbaux, J. Hadji-Lazaro, D. Hurtmans |
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 ; 7, no. 12 ; Nr. 7, no. 12 (2014-12-08), S.4223-4236 |
Datensatznummer |
250115981
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Publikation (Nr.) |
copernicus.org/amt-7-4223-2014.pdf |
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Zusammenfassung |
We apply the Tropospheric Emission Spectrometer (TES) ozone retrieval
algorithm to Infrared Atmospheric Sounding Instrument (IASI) radiances and
characterise the uncertainties and information content of the retrieved ozone
profiles. This study focuses on mid-latitudes for the year 2008. We validate
our results by comparing the IASI ozone profiles to ozone sondes. In the
sonde comparisons, we find a negative bias (1–10%) in the IASI profiles
in the lower to mid-troposphere and a positive bias (up to 14%) in the upper
troposphere/lower stratosphere
(UTLS) region. For the described cases, the degrees of freedom for signal are
on average 3.2, 0.3, 0.8, and 0.9 for the columns 0 km – top of atmosphere,
(0–6), (0–11), and (8–16) km, respectively. We find that our biases with
respect to sondes and our degrees of freedom for signal for ozone are
comparable to previously published results from other IASI ozone algorithms.
In addition to evaluating biases, we validate the retrieval errors by
comparing predicted errors to the sample covariance matrix of the IASI
observations themselves. For the predicted versus empirical error
comparison, we find that these errors are consistent and that the measurement
noise and the interference of temperature and water vapour on the retrieval
together mostly explain the empirically derived random errors. In general,
the precision of the IASI ozone profiles is better than 20%. |
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