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| Titel |
Improving ozone profile retrieval from spaceborne UV backscatter spectrometers using convergence behaviour diagnostics |
| VerfasserIn |
B. Mijling, O. N. E. Tuinder, R. F. Oss, R. J. der A. |
| 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 ; 3, no. 6 ; Nr. 3, no. 6 (2010-11-12), S.1555-1568 |
| Datensatznummer |
250001359
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| Publikation (Nr.) |
 copernicus.org/amt-3-1555-2010.pdf |
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| Zusammenfassung |
The Ozone Profile Algorithm (OPERA), developed at KNMI, retrieves the
vertical ozone distribution from nadir spectral satellite measurements of
back scattered sunlight in the ultraviolet and visible wavelength range. To
produce consistent global datasets the algorithm needs to have good global
performance, while short computation time facilitates the use of the
algorithm in near real time applications.
To test the global performance of the algorithm we look at the convergence
behaviour as diagnostic tool of the ozone profile retrievals from the GOME
instrument (on board ERS-2) for February and October 1998. In this way, we
uncover different classes of retrieval problems, related to the South
Atlantic Anomaly, low cloud fractions over deserts, desert dust outflow over
the ocean, and the intertropical convergence zone. The influence of the
first guess and the external input data including the ozone cross-sections
and the ozone climatologies on the retrieval performance is also
investigated. By using a priori ozone profiles which are selected on the expected
total ozone column, retrieval problems due to anomalous ozone distributions
(such as in the ozone hole) can be avoided.
By applying the algorithm adaptations the convergence statistics improve
considerably, not only increasing the number of successful retrievals, but
also reducing the average computation time, due to less iteration steps per
retrieval. For February 1998, non-convergence was brought down from 10.7%
to 2.1%, while the mean number of iteration steps (which dominates the
computational time) dropped 26% from 5.11 to 3.79. |
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