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| Titel |
Sulfur dioxide (SO2) as observed by MIPAS/Envisat: temporal development and spatial distribution at 15–45 km altitude |
| VerfasserIn |
M. Höpfner, N. Glatthor, U. Grabowski, S. Kellmann, M. Kiefer, A. Linden, J. Orphal, G. Stiller, T. von Clarmann, B. Funke, C. D. Boone |
| 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 ; 13, no. 20 ; Nr. 13, no. 20 (2013-10-29), S.10405-10423 |
| Datensatznummer |
250085770
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| Publikation (Nr.) |
 copernicus.org/acp-13-10405-2013.pdf |
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| Zusammenfassung |
| We present a climatology of monthly and 10° zonal mean profiles of
sulfur dioxide (SO2) volume mixing ratios (vmr) derived from MIPAS/Envisat
measurements in the altitude range 15–45 km from July 2002 until April
2012. The vertical resolution varies from 3.5–4 km in the lower
stratosphere up to 6–10 km at the upper end of the profiles, with estimated
total errors of 5–20 pptv for single profiles of SO2. Comparisons with
the few available observations of SO2 up to high altitudes from ATMOS
for a volcanically perturbed situation from ACE-FTS and, at the lowest
altitudes, with stratospheric in situ observations reveal general consistency
of the datasets. The observations are the first empirical confirmation of
features of the stratospheric SO2 distribution, which have only been shown
by models up to now: (1) the local maximum of SO2 at around 25–30 km
altitude, which is explained by the conversion of carbonyl sulfide (COS) as
the precursor of the Junge layer; and (2) the downwelling of SO2-rich air
to altitudes of 25–30 km at high latitudes during winter and its subsequent
depletion on availability of sunlight. This has been proposed as the reason
for the sudden appearance of enhanced concentrations of condensation nuclei
during Arctic and Antarctic spring. Further, the strong increase of SO2 to
values of 80–100 \unit{pptv} in the upper stratosphere through photolysis
of H2SO4 has been confirmed. Lower stratospheric variability of SO2
could mainly be explained by volcanic activity, and no hints of a strong
anthropogenic influence have been found. Regression analysis revealed a QBO
(quasi-biennial oscillation) signal of the SO2 time series in the tropics
at about 30–35 km, an SAO (semi-annual oscillation) signal at tropical and
subtropical latitudes above 32 km and annual periodics predominantly at high
latitudes. Further, the analysis indicates a correlation with the solar cycle
in the tropics and southern subtropics above 30 km. Significant negative
linear trends are found in the tropical lower stratosphere, probably due to
reduced tropical volcanic activity and at southern mid-latitudes above
35 km. A positive trend is visible in the lower and middle stratosphere at
polar to subtropical southern latitudes. |
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