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| Titel |
Could aerosol emissions be used for regional heat wave mitigation? |
| VerfasserIn |
D. N. Bernstein, J. D. Neelin, Q. B. Li, D. Chen |
| 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. 13 ; Nr. 13, no. 13 (2013-07-05), S.6373-6390 |
| Datensatznummer |
250018739
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| Publikation (Nr.) |
 copernicus.org/acp-13-6373-2013.pdf |
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| Zusammenfassung |
| Geoengineering applications by injection of sulfate aerosols into the
stratosphere are under consideration as a measure of last resort to counter
global warming. Here a potential regional-scale application to offset the
impacts of heat waves is critically examined. Using the Weather Research and Forecasting model with fully coupled
chemistry (WRF-Chem), the effect of regional-scale
sulfate aerosol emission over California in each of two days of the July 2006
heat wave is used to quantify potential reductions in surface
temperature as a function of emission rates in a layer at 12 km altitude.
Local meteorological factors yield geographical differences in surface air
temperature sensitivity. For emission rates of approximately
30 μg m−2 s−1 of sulfate aerosols (with standard
WRF-Chem size distribution) over the region, temperature decreases of around
7 °C result during the middle part of the day over the Central
Valley, one of the areas hardest hit by the heat wave. Regions more ventilated with
oceanic air such as Los Angeles have slightly smaller reductions. The length
of the hottest part of the day is also reduced. Advection effects on the
aerosol cloud must be more carefully forecast for smaller injection regions.
Verification of the impacts could be done via measurements of differences in
reflected and surface downward shortwave. Such regional geoengineering
applications with specific near-term target effects but smaller cost and side
effects could potentially provide a means of testing larger scale
applications. However, design considerations for regional applications, such
as a preference for injection at a level of relatively low wind speed, differ
from those for global applications. The size of the required injections and
the necessity of injection close to the target region raise substantial
concerns. The evaluation of this regional-scale application is thus
consistent with global model evaluations, emphasizing that mitigation via
reduction of fossil fuels remains preferable to considering geoengineering
with sulfate aerosols. |
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