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Titel |
Cenozoic climate evolution in Asian region and its influence on isotopic composition of precipitation |
VerfasserIn |
Svetlana Botsyun, Yannick Donnadieu, Pierre Sepulchre, Camille Risi, Frédéric Fluteau |
Konferenz |
EGU General Assembly 2015
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 17 (2015) |
Datensatznummer |
250107511
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Publikation (Nr.) |
EGU/EGU2015-7214.pdf |
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Zusammenfassung |
The evolution of Asian climate during the Cenozoic as well as the onset of monsoon systems
in this area is highly debated. Factors that control climate include the geographical
position of continents, the land-sea distribution and altitude of orogens. In tern,
several climatic parameters such as air temperature, precipitation amount and isotopic
fractionation through mass-dependent processes impact precipitation δ18O lapse rate.
Stable oxygen paleoaltimetry is considered to be a very efficient and widely applied
technique, but the link between stable oxygen composition of precipitation and climate
is not well established. To quantify the influence of paleogeography changes on
climate and precipitation δ18O over Asia, the atmospheric general circulation model
LMDZ-iso, with embedded stable oxygen isotopes, was used. For more realistic
experiments, sea surface temperatures were calculated with the fully coupled model
FOAM. Various scenarios of TP growth have been applied together with Paleocene,
Eocene, Oligocene and Miocene boundary conditions. The results of our numerical
modelling show a significant influence of paleogeography changes on the Asian
climate. The retreat of the Paratethys ocean, the changes in latitudinal position
of India, and the height of the Tibetan Plateau most likely control precipitation
patterns over Asia and cause spatial and temporal isotopic variations linked with the
amount effect. Indian Ocean currents restructuring during the Eocene induces a
substantial warming over Asian continent. The adiabatic and non-adiabatic temperature
effects explain some of δ18O signal variations. We highlight the importance of these
multiple factor on paleoelevations estimates derived using oxygen stable isotopes. |
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