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| Titel |
Sensitivity simulations with direct shortwave radiative forcing by aeolian dust during glacial cycles |
| VerfasserIn |
E. Bauer, A. Ganopolski |
| 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 ; 10, no. 4 ; Nr. 10, no. 4 (2014-07-17), S.1333-1348 |
| Datensatznummer |
250117015
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| Publikation (Nr.) |
 copernicus.org/cp-10-1333-2014.pdf |
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| Zusammenfassung |
| Possible feedback effects between aeolian dust, climate and ice sheets are studied for the first
time with an Earth system model of intermediate complexity over the late Pleistocene
period. Correlations between climate and dust deposition records suggest that aeolian dust
potentially plays an important role for the evolution of glacial cycles. Here climatic effects
from the dust direct radiative forcing (DRF) caused by absorption and scattering of solar
radiation are investigated. Key elements controlling the dust DRF are the atmospheric dust
distribution and the absorption-scattering efficiency of dust aerosols. Effective physical
parameters in the description of these elements are varied within uncertainty ranges known from
available data and detailed model studies. Although the parameters can be reasonably constrained, the simulated
dust DRF spans a~wide uncertainty range related to the strong nonlinearity of the Earth system. In our simulations,
the dust DRF is highly localized. Medium-range parameters result
in negative DRF of several watts per square metre in regions close to major dust sources and negligible
values elsewhere. In the case of high absorption efficiency, the local dust DRF can reach positive
values and the global mean DRF can be insignificantly small. In the case of low absorption efficiency,
the dust DRF can produce a significant global cooling in glacial periods, which leads to a doubling
of the maximum glacial ice volume relative to the case with small dust DRF. DRF-induced
temperature and precipitation changes can either be attenuated or amplified through a feedback
loop involving the dust cycle. The sensitivity experiments suggest that depending on dust optical
parameters, dust DRF has the potential to either damp or reinforce glacial–interglacial climate changes. |
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