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| Titel |
An evaluation of the SAGE III version 4 aerosol extinction coefficient and water vapor data products |
| VerfasserIn |
L. W. Thomason, J. R. Moore, M. C. Pitts, J. M. Zawodny, E. W. Chiou |
| 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 ; 10, no. 5 ; Nr. 10, no. 5 (2010-03-01), S.2159-2173 |
| Datensatznummer |
250008162
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| Publikation (Nr.) |
 copernicus.org/acp-10-2159-2010.pdf |
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| Zusammenfassung |
| Herein, we provide an assessment of the data quality of Stratospheric
Aerosol and Gas Experiment (SAGE III) Version 4 aerosol extinction
coefficient and water vapor data products. The evaluation is based on
comparisons with data from four instruments: SAGE II, the Polar Ozone and
Aerosol Measurement (POAM III), the Halogen Occultation Experiment (HALOE),
and the Microwave Limb Sounder (MLS). Since only about half of the SAGE III
channels have a direct comparison with measurements by other instruments, we
have employed some empirical techniques to evaluate measurements at some
wavelengths. We find that the aerosol extinction coefficient measurements at
449, 520, 755, 869, and 1021 nm are reliable with accuracies and precisions
on the order of 10% in the mission's primary aerosol target range of 15
to 25 km. We also believe this to be true of the aerosol measurements at
1545 nm though we cannot exclude some positive bias below 15 km. We
recommend use of the 385 nm measurements above 16 km where the accuracy is
on par with other aerosol channels. The 601 nm measurement is much noisier
(~20%) than other channels and we suggest caution in the use of
these data. We believe that the 676 nm data are clearly defective
particularly above 20 km (accuracy as poor as 50%) and the precision is
also low (~30%). We suggest excluding this channel under most
circumstances. The SAGE III Version 4 water vapor data product appears to be
high quality and is recommended for science applications in the stratosphere
below 45 km. In this altitude range, the mean differences with all four
corroborative data sets are no bigger than 15% and often less than 10%
with exceptional agreement with POAM III and MLS. Above 45 km, it seems
likely that SAGE III water vapor values are increasingly too large and
should be used cautiously or avoided. We believe that SAGE III meets its
preflight goal of 15% accuracy and 10% precision between 15 and 45 km.
SAGE III water vapor data does not appear to be affected by aerosol loading
in the stratosphere. |
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