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Titel |
Microphysical simulations of sulfur burdens from stratospheric sulfur geoengineering |
VerfasserIn |
J. M. English, O. B. Toon, M. J. Mills |
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 ; 12, no. 10 ; Nr. 12, no. 10 (2012-05-31), S.4775-4793 |
Datensatznummer |
250011179
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Publikation (Nr.) |
copernicus.org/acp-12-4775-2012.pdf |
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Zusammenfassung |
Recent microphysical studies suggest that geoengineering by continuous
stratospheric injection of SO2 gas may be limited by the growth of the
aerosols. We study the efficacy of SO2, H2SO4 and aerosol
injections on aerosol mass and optical depth using a three-dimensional
general circulation model with sulfur chemistry and sectional aerosol
microphysics (WACCM/CARMA). We find increasing injection rates of SO2
in a narrow band around the equator to have limited efficacy while
broadening the injecting zone as well as injecting particles instead of
SO2 gas increases the sulfate burden for a given injection rate, in
agreement with previous work. We find that injecting H2SO4 gas
instead of SO2 does not discernibly alter sulfate size or mass, in
contrast with a previous study using a plume model with a microphysical
model. However, the physics and chemistry in aircraft plumes, which are
smaller than climate model grid cells, need to be more carefully considered.
We also find significant perturbations to tropospheric aerosol for all
injections studied, particularly in the upper troposphere and near the
poles, where sulfate burden increases by up to 100 times. This enhanced
burden could have implications for tropospheric radiative forcing and
chemistry. These results highlight the need to mitigate greenhouse gas
emissions rather than attempt to cool the planet through geoengineering, and
to further study geoengineering before it can be seriously considered as a
climate intervention option. |
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