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| Titel |
Climate response to imposed solar radiation reductions in high latitudes |
| VerfasserIn |
M. C. MacCracken, H.-J. Shin, K. Caldeira, G. A. Ban-Weiss |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2190-4979
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| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 4, no. 2 ; Nr. 4, no. 2 (2013-09-02), S.301-315 |
| Datensatznummer |
250084953
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| Publikation (Nr.) |
 copernicus.org/esd-4-301-2013.pdf |
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| Zusammenfassung |
| With human-induced climate change leading to amplified warming in high
latitudes, mitigation alone is unlikely to be rapid enough to prevent
significant, even irreversible, impacts. Model simulations in which solar
insolation was arbitrarily reduced poleward of 51, 61, or 71°
latitude in one or both hemispheres not only cooled those regions, but also
drew energy from lower latitudes, exerting a cooling influence over much of
the particular hemisphere in which the reduction was imposed. The
simulations, conducted using the National Center for Atmospheric Research's
CAM3.1 atmospheric model coupled to a slab ocean, indicated that
high-latitude reductions in absorbed solar radiation have a significantly
larger cooling influence than solar reductions of equivalent magnitude
spread evenly over the Earth. This amplified influence occurred primarily
because concentrated high-latitude reductions in solar radiation led to
increased sea ice fraction and surface albedo, thereby amplifying the energy
deficit at the top of the atmosphere as compared to the response for an
equivalent reduction in solar radiation spread evenly over the globe.
Reductions in incoming solar radiation in one polar region (either north or
south) resulted in increased poleward energy transport during that
hemisphere's cold season and shifted the Inter-Tropical Convergence Zone
(ITCZ) away from that pole, whereas comparable solar reductions in both
polar regions resulted in increased poleward energy transport, but tended to
leave the ITCZ approximately in place. Together, these results suggest that,
until emissions reductions are sufficient to limit the warming influence of
increasing greenhouse gas concentrations, polar reductions in solar
radiation, if they could be efficiently and effectively implemented, warrant
further research as an approach to moderating the early stages of both
high-latitude and global warming. |
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