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| Titel |
Radiative effects of ozone on the climate of a Snowball Earth |
| VerfasserIn |
J. Yang, Y. Hu, W. R. Peltier |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 8, no. 6 ; Nr. 8, no. 6 (2012-12-10), S.2019-2029 |
| Datensatznummer |
250005983
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| Publikation (Nr.) |
 copernicus.org/cp-8-2019-2012.pdf |
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| Zusammenfassung |
Some geochemical and geological evidence has been interpreted to suggest that the
concentration of atmospheric oxygen was only 1–10 % of the
present level in the time interval from 750 to 580 million years ago
when several nearly global glaciations or Snowball Earth events
occurred. This low concentration of oxygen would have been
accompanied by a lower ozone concentration than exists at present. Since ozone
is a greenhouse gas, this change in ozone concentration would alter
surface temperature, and thereby could have an important influence
on the climate of the Snowball Earth. Previous works that have focused either on
initiation or deglaciation of the proposed Snowball Earth has not
taken the radiative effects of ozone changes into account. We
address this issue herein by performing a series of simulations
using an atmospheric general circulation model with various ozone
concentrations.
Our simulation results demonstrate that, as ozone concentration is
uniformly reduced from 100 % to 50 %, surface
temperature decreases by approximately 0.8 K at the Equator,
with the largest decreases located in the middle latitudes reaching
as high as 2.5 K. When ozone concentration is reduced and its
vertical and horizontal distribution is simultaneously modulated,
surface temperature decreases by 0.4–1.0 K at the Equator
and by 4–7 K in polar regions. These results here have uncertainties, depending
on model parameterizations of cloud, surface snow albedo, and relevant feedback processes,
while they are qualitatively consistent with radiative-convective model results
that do not involve such parameterizations and feedbacks. These results suggest
that ozone variations could have had a moderate impact on the climate during the Neoproterozoic glaciations. |
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