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| Titel |
Modulation of the intraseasonal Indo-western Pacific convection oscillation to tropical cyclogenesis location and frequency over the Indo-western North Pacific during boreal extended summer |
| VerfasserIn |
Qiuyun Wang, Jianping Li, Yanjie Li, Jingwen Zhang |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250142563
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| Publikation (Nr.) |
 EGU/EGU2017-6198.pdf |
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| Zusammenfassung |
| The influence of the intraseasonal Indo-western Pacific convection oscillation (IPCO) on the
tropical cyclone (TC) genesis location and frequency over the Indo-western North Pacific
during the boreal extended summer (May-October) is explored in this paper. Observational
analysis shows that the impacts of the intraseasonal IPCO on TCs over the Indo-western
North Pacific features in evident “locational phase lock of TC genesis” and distinct
differences in TC frequency. In term of the WNP, when the intraseasonal IPCO is positive
phase, there tends to be much more TCs, especially in the South China Sea (SCS), and
more TCs generate in the west of the WNP and lower latitude (around 5º-20ºN);
vice versa. At the positive intraseasonal IPCO phase, the atmosphere gains heat
through both sea-air interaction and the latent heat release of cumulus convective
condensation, and the anomalous cyclonic circulation weakens the western Pacific
subtropical high (WPSH), these conditions do favor the TC genesis. Moreover, the
shrinking WPSH, the enhanced heat transfer from sea to air at the lower latitude as
well as the westward shifts of heating center and anomalous cyclonic circulation
lock TC genesis locations in the west of the WNP and lower latitude. The opposite
situation occurs at negative phase. As for the North Indian Ocean (NIO), the TC
genesis locations at the positive intraseasonal IPCO phase mainly situate in 13º-20ºN and
distribute closer to Indian Peninsula, particularly in the Arabian Sea (ARB), in
contrast, the spatial distribution is more dispersed at the negative intraseasonal
IPCO phase. However, the total TC frequencies at two intraseasonal IPCO phases
are similar. These features come largely from the differences in the area featuring
conditions between the northern and southern regions of 13ºN in the NIO: at the
positive intraseasonal IPCO phase, to the northern region of 13ºN, the environmental
conditions are similar to the case of the WNP except without the WPSH control, and the
reversed situations are observed over the southern region of 13ºN, which lead to
northward shift of TC genesis location. The negative phase reflects an opposite situation. |
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