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| Titel |
Toward a combined SAGE II-HALOE aerosol climatology: an evaluation of HALOE version 19 stratospheric aerosol extinction coefficient observations |
| VerfasserIn |
L. W. Thomason |
| 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 ; 12, no. 17 ; Nr. 12, no. 17 (2012-09-12), S.8177-8188 |
| Datensatznummer |
250011440
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| Publikation (Nr.) |
 copernicus.org/acp-12-8177-2012.pdf |
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| Zusammenfassung |
| Herein, the Halogen Occultation Experiment (HALOE) aerosol extinction
coefficient data is evaluated in the low aerosol loading period after 1996
as the first necessary step in a process that will eventually allow the
production of a combined HALOE/SAGE II (Stratospheric Aerosol and Gas
Experiment) aerosol climatology of derived aerosol products including
surface area density. Based on these analyses, it is demonstrated that
HALOE's 3.46 μm is of good quality above 19 km and suitable for
scientific applications above that altitude. However, it is increasingly
suspect at lower altitudes and should not be used below 17 km under any
circumstances after 1996. The 3.40 μm is biased by about 10%
throughout the lower stratosphere due to the failure to clear NO2 but
otherwise appears to be a high quality product down to 15 km. The 2.45 and
5.26 μm aerosol extinction coefficient measurements are clearly biased
and should not be used for scientific applications after the most intense
parts of the Pinatubo period. Many of the issues in the aerosol data appear
to be related to either the failure to clear some interfering gas species or
doing so poorly. For instance, it is clear that the 3.40 μm aerosol
extinction coefficient measurements can be improved through the inclusion of
an NO2 correction and could, in fact, end up as the highest quality
overall HALOE aerosol extinction coefficient measurement. It also appears
that the 2.45 and 5.26 μm channels may be improved by updating the
Upper Atmosphere Pilot Database which is used as a resource for the removal
of gas species otherwise not available from direct HALOE measurements.
Finally, a simple model to demonstrate the promise of mixed visible/infrared
aerosol extinction coefficient ensembles for the retrieval of bulk aerosol
properties demonstrates that a combined HALOE/SAGE II aerosol climatology is
feasible and may represent a substantial improvement over independently
derived data sets. |
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