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| Titel |
Characterization of Odin-OSIRIS ozone profiles with the SAGE II dataset |
| VerfasserIn |
C. Adams, A. E. Bourassa, A. F. Bathgate, C. A. McLinden, N. D. Lloyd, C. Z. Roth, E. J. Llewellyn, J. M. Zawodny, D. E. Flittner, G. L. Manney, W. H. Daffer, D. A. Degenstein |
| 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. 5 ; Nr. 6, no. 5 (2013-05-29), S.1447-1459 |
| Datensatznummer |
250017904
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| Publikation (Nr.) |
 copernicus.org/amt-6-1447-2013.pdf |
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| Zusammenfassung |
| The Optical Spectrograph and InfraRed Imaging System (OSIRIS) on board the
Odin spacecraft has been taking limb-scattered measurements of ozone number
density profiles from 2001–present. The Stratospheric Aerosol and Gas
Experiment II (SAGE II) took solar occultation measurements of ozone number
densities from 1984–2005 and has been used in many studies of long-term
ozone trends. We present the characterization of OSIRIS SaskMART v5.0×
against the new SAGE II v7.00 ozone profiles for 2001–2005, the period over
which these two missions had overlap. This information can be used to merge
OSIRIS with SAGE II into a single ozone record from 1984 to the present, if
other satellite ozone measurements are included to account for gaps in the
OSIRIS dataset in the winter hemisphere. Coincident measurement pairs were
selected for ±1 h, ±1° latitude, and ±500 km.
The absolute value of the resulting mean relative difference profile is
<5% for 13.5–54.5 km and <3% for 24.5–53.5 km.
Correlation coefficients R > 0.9 were calculated for 13.5–49.5 km,
demonstrating excellent overall agreement between the two datasets.
Coincidence criteria were relaxed to maximize the number of measurement
pairs and the conditions under which measurements were taken. With the broad
coincidence criteria, good agreement (< 5%) was observed under
most conditions for 20.5–40.5 km. However, mean relative differences do
exceed 5% for several cases. Above 50 km, differences between OSIRIS and
SAGE II are partly attributed to the diurnal variation of ozone. OSIRIS data
are biased high compared with SAGE II at 22.5 km, particularly at high
latitudes. Dynamical coincidence criteria, using derived meteorological
products, were also tested and yielded similar overall results, with slight
improvements to the correlation at high latitudes. The OSIRIS optics
temperature is low (<16 °C) during May–July, when the
satellite enters the Earth's shadow for part of its orbit. During this
period, OSIRIS measurements are biased low by 5–12% for 27.5–38.5 km.
Biases between OSIRIS ascending node (northward equatorial crossing time
~18:00 LT – local time) and descending node (southward equatorial crossing
time ~06:00 LT) measurements are also noted under some
conditions. This work demonstrates that OSIRIS and SAGE II have excellent
overall agreement and characterizes the biases between these datasets. |
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