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| Titel |
Regional climate model experiments to investigate the Asian monsoon in the Late Miocene |
| VerfasserIn |
H. Tang, A. Micheels, J. Eronen, M. Fortelius |
| 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 ; 7, no. 3 ; Nr. 7, no. 3 (2011-08-09), S.847-868 |
| Datensatznummer |
250004614
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| Publikation (Nr.) |
 copernicus.org/cp-7-847-2011.pdf |
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| Zusammenfassung |
| The Late Miocene (11.6–5.3 Ma) is a crucial period in the history of the
Asian monsoon. Significant changes in the Asian climate regime have been
documented for this period, which saw the formation of the modern Asian
monsoon system. However, the spatiotemporal structure of these changes is
still ambiguous, and the associated mechanisms are debated. Here, we present
a simulation of the average state of the Asian monsoon climate
for the Tortonian (11–7 Ma) using
the regional climate model CCLM3.2. We employ relatively high spatial
resolution (1° × 1°) and adapt the physical boundary
conditions such as topography, land-sea distribution and vegetation in the
regional model to represent the Late Miocene. As climatological forcing, the
output of a Tortonian run with a fully-coupled atmosphere-ocean general
circulation model is used. Our regional Tortonian run shows a
stronger-than-present East Asian winter monsoon wind as a result of the
enhanced mid-latitude westerly wind of our global forcing and the lowered
present-day northern Tibetan Plateau in the regional model. The summer
monsoon circulation is generally weakened in our regional Tortonian run
compared to today. However, the changes of summer monsoon precipitation
exhibit major regional differences. Precipitation decreases in northern China
and northern India, but increases in southern China, the western coast and
the southern tip of India. This can be attributed to the changes in both the
regional topography (e.g. the lower northern Tibetan Plateau) and the global
climate conditions (e.g. the higher sea surface temperature). The spread of
dry summer conditions over northern China and northern Pakistan in our
Tortonian run further implies that the monsoonal climate may not have been
fully established in these regions in the Tortonian. Compared with the global
model, the high resolution regional model highlights the spatial differences
of the Asian monsoon climate in the Tortonian, and better characterizes the
convective activity and its response to regional topographical changes. It
therefore provides a useful and compared to global models, a complementary tool
to improve our understanding of the Asian monsoon evolution in the Late
Miocene. |
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