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| Titel |
Monsoonal response to mid-holocene orbital forcing in a high resolution GCM |
| VerfasserIn |
J. H. C. Bosmans, S. S. Drijfhout, E. Tuenter, L. J. Lourens, F. J. Hilgen, S. L. Weber |
| 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 ; 8, no. 2 ; Nr. 8, no. 2 (2012-04-03), S.723-740 |
| Datensatznummer |
250005480
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| Publikation (Nr.) |
 copernicus.org/cp-8-723-2012.pdf |
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| Zusammenfassung |
| In this study, we use a sophisticated high-resolution atmosphere-ocean coupled
climate model, EC-Earth, to investigate the effect of Mid-Holocene orbital
forcing on summer monsoons on both hemispheres. During the Mid-Holocene (6 ka),
there was more summer insolation on the Northern Hemisphere than today,
which intensified the meridional temperature and pressure gradients. Over
North Africa, monsoonal precipitation is intensified through increased
landward monsoon winds and moisture advection as well as decreased moisture
convergence over the oceans and more convergence over land compared to the
pre-industrial simulation. Precipitation also extends further north as the
ITCZ shifts northward in response to the stronger poleward gradient of
insolation. This increase and poleward extent is stronger than in most
previous ocean-atmosphere GCM simulations. In north-westernmost Africa,
precipitation extends up to 35° N. Over tropical Africa, internal
feedbacks completely overcome the direct warming effect of increased
insolation. We also find a weakened African Easterly Jet. Over Asia,
monsoonal precipitation during the Mid-Holocene is increased as well, but the
response is different than over North-Africa. There is more convection over
land at the expense of convection over the ocean, but precipitation does not
extend further northward, monsoon winds over the ocean are weaker and the
surrounding ocean does not provide more moisture. On the Southern Hemisphere,
summer insolation and the poleward insolation gradient were weaker during the
Mid-Holocene, resulting in a reduced South American monsoon through decreased
monsoon winds and less convection, as well as an equatorward shift in the
ITCZ. This study corroborates the findings of paleodata research as well as
previous model studies, while giving a more detailed account of Mid-Holocene
monsoons. |
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