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Titel |
A new ENSO index derived from satellite measurements of column ozone |
VerfasserIn |
J. R. Ziemke, S. Chandra, L. D. Oman, P. K. Bhartia |
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. 8 ; Nr. 10, no. 8 (2010-04-21), S.3711-3721 |
Datensatznummer |
250008367
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Publikation (Nr.) |
copernicus.org/acp-10-3711-2010.pdf |
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Zusammenfassung |
Column Ozone measured in tropical latitudes from
Nimbus 7 total ozone mapping spectrometer (TOMS), Earth Probe TOMS, solar
backscatter ultraviolet (SBUV), and Aura ozone monitoring instrument (OMI)
are used to derive an El Nino-Southern Oscillation (ENSO) index. This index,
which covers a time period from 1979 to the present, is defined as the
"Ozone ENSO Index" (OEI) and is the first developed from atmospheric trace
gas measurements. The OEI is constructed by first averaging monthly mean
column ozone over two broad regions in the western and eastern Pacific and
then taking their difference. This differencing yields a self-calibrating
ENSO index which is independent of individual instrument calibration offsets
and drifts in measurements over the long record. The combined Aura OMI and
MLS ozone data confirm that zonal variability in total column ozone in the
tropics caused by ENSO events lies almost entirely in the troposphere. As a
result, the OEI can be derived directly from total column ozone instead of
tropospheric column ozone. For clear-sky ozone measurements a +1 K change in
Nino 3.4 index corresponds to +2.9 Dobson Unit (DU) change in the OEI, while
a +1 hPa change in SOI coincides with a −1.7 DU change in the OEI. For ozone
measurements under all cloud conditions these numbers are +2.4 DU and
−1.4 DU, respectively. As an ENSO index based upon ozone, it is potentially
useful in evaluating climate models predicting long term changes in ozone
and other trace gases. |
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