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Titel |
Reexamining the barrier effect of the Tibetan Plateau on the South Asian summer monsoon |
VerfasserIn |
G.-S. Chen, Z. Liu, J. E. Kutzbach |
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. 3 ; Nr. 10, no. 3 (2014-06-30), S.1269-1275 |
Datensatznummer |
250116991
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Publikation (Nr.) |
copernicus.org/cp-10-1269-2014.pdf |
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Zusammenfassung |
The Tibetan Plateau has been conventionally treated as an elevated heat
source driving the Asian monsoon system, especially for the South Asian
monsoon. Numerous model simulations with general circulation models (GCMs)
support this hypothesis with the finding that the Asian monsoon system is
weak or absent when all elevated topography is removed. A recent model
simulation shows that the South Asian summer monsoon circulation is little
affected with only the Himalayas (no-Tibetan Plateau) kept as a barrier,
leading to a hypothesis of the barrier "blocking" mechanism of the Tibetan
Plateau. In this paper, a new series of experiments are designed to reexamine
this barrier effect. We find that with the barrier, the large-scale summer
monsoon circulation over South Asia is simulated in general agreement with
the full Tibetan Plateau, which is consistent with the previous finding.
However, there remains significant differences in both wind and precipitation
fields, suggesting a role for the full Tibetan Plateau as well. Moreover, the
proposed barrier blocking mechanism is not found in our experiments. The
energy of the low-level air and the convection are lower and weaker over the
Indian subcontinent in the full Tibetan Plateau experiment than that in the
no-Tibetan Plateau experiment or the barrier only experiment, which is in
contrast to the barrier blocking hypothesis. Instead, there is a similar
candle-like latent heating in the middle troposphere along the southern edge
of the Tibetan Plateau in both the full Tibetan Plateau and the barrier
experiments, whereas this "candle heating" disappears in the no-Tibetan
Plateau experiment. We propose that this candle heating is the key to
understanding the mechanisms of the Tibetan Plateau on the South Asian
monsoon. Future studies are needed to check the source of the "candle
heating" and its effect on the Asian monsoon. |
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