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Titel |
Solar Backscatter UV (SBUV) total ozone and profile algorithm |
VerfasserIn |
P. K. Bhartia, R. D. McPeters, L. E. Flynn, S. Taylor, N. A. Kramarova, S. Frith, B. Fisher, M. DeLand |
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 ; 6, no. 10 ; Nr. 6, no. 10 (2013-10-07), S.2533-2548 |
Datensatznummer |
250085073
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Publikation (Nr.) |
copernicus.org/amt-6-2533-2013.pdf |
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Zusammenfassung |
We describe the algorithm that has been applied to develop a 42 yr record of
total ozone and ozone profiles from eight Solar Backscatter UV (SBUV)
instruments launched on NASA and NOAA satellites since April 1970. The
Version 8 (V8) algorithm was released more than a decade ago and has been in
use since then at NOAA to produce their operational ozone products. The
current algorithm (V8.6) is basically the same as V8, except for updates to
instrument calibration, incorporation of new ozone absorption cross-sections,
and new ozone and cloud height climatologies. Since the V8 algorithm has been
optimized for deriving monthly zonal mean (MZM) anomalies for ozone
assessment and model comparisons, our emphasis in this paper is primarily on
characterizing the sources of errors that are relevant for such studies. When
data are analyzed this way the effect of some errors, such as vertical
smoothing of short-term variability, and noise due to clouds and aerosols
diminish in importance, while the importance of others, such as errors due to
vertical smoothing of the quasi-biennial oscillation (QBO) and other periodic and aperiodic variations, become
more important. With V8.6 zonal mean data we now provide smoothing kernels
that can be used to compare anomalies in SBUV profile and partial ozone
columns with models. In this paper we show how to use these kernels to
compare SBUV data with Microwave Limb Sounder (MLS) ozone profiles. These kernels are particularly
useful for comparisons in the lower stratosphere where SBUV profiles have
poor vertical resolution but partial column ozone values have high accuracy.
We also provide our best estimate of the smoothing errors associated with
SBUV MZM profiles. Since smoothing errors are the largest source of
uncertainty in these profiles, they can be treated as error bars in deriving
interannual variability and trends using SBUV data and for comparing with
other measurements. In the V8 and V8.6 algorithms we derive total column
ozone by integrating the SBUV profiles, rather than from a separate set of
wavelengths, as was done in previous algorithm versions. This allows us to
extend the total ozone retrieval to 88° solar zenith angle (SZA).
Since the quality of total column data is affected by reduced sensitivity to
ozone in the lower atmosphere by cloud and Rayleigh attenuation, which gets
worse with increasing SZA, we provide our best estimate of these errors, as
well as the kernels that can be used to test the sensitivity of the derived
columns to long-term changes in ozone in the lower atmosphere. |
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