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| Titel |
Mending Milankovitch's theory: obliquity amplification by surface feedbacks |
| VerfasserIn |
C. R. Tabor, C. J. Poulsen, D. Pollard |
| 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. 1 ; Nr. 10, no. 1 (2014-01-10), S.41-50 |
| Datensatznummer |
250116893
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| Publikation (Nr.) |
 copernicus.org/cp-10-41-2014.pdf |
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| Zusammenfassung |
| Milankovitch's theory states that orbitally induced changes in high-latitude
summer insolation dictate the waxing and waning of ice sheets. Accordingly,
precession should dominate the ice-volume response because it most strongly
modulates summer insolation. However, early Pleistocene
(2.588–0.781 Ma) ice-volume proxy records vary almost exclusively at
the frequency of the obliquity cycle. To explore this paradox, we use an
Earth system model coupled with a dynamic ice sheet to separate the climate
responses to idealized transient orbits of obliquity and precession that
maximize insolation changes. Our results show that positive surface albedo
feedbacks between high-latitude annual-mean insolation, ocean heat flux and
sea-ice coverage, and boreal forest/tundra exchange enhance the ice-volume
response to obliquity forcing relative to precession forcing. These surface
feedbacks, in combination with modulation of the precession cycle power by
eccentricity, help explain the dominantly 41 kyr cycles in global ice
volume of the early Pleistocene. |
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