著者

Masamichi OHBA Hiroaki UEDA

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.85, no.3, pp.335-348, 2007 (Released:2007-08-09)

参考文献数

46

被引用文献数

59 77

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One possible impact of sea surface temperature (SST) anomalies in the Indian Ocean (IO) on the ongoing El Niño is investigated using an air-sea coupled general circulation model (CGCM). A suite of CGCM experiments by imposing the IO basin-wide warming (BW) and IO dipole/zonal mode (IODZM) are conducted to assess the feedback effects of the El Niño-related SST anomalies on the Pacific. While the IODZM during boreal fall does not have a significant impact on the Pacific sector, the BW during boreal winter enhances the surface easterlies over the equatorial Western Pacific (WP) during the maturedecay phase of El Niño. The strengthened easterlies act to enhance the SST cooling over the WP, thereby the zonal gradient of SST between the IO and WP is greater than the climatology. These enhanced WP easterlies induce an advanced transition to the La Niña phase, which is caused by the upwelling ocean Kelvin waves. These results imply that the BW in the IO, to some extent, can be hastening the El Niño to La Niña transition.

著者

Masamichi Ohba Hiroaki Ueda

出版者

(公社)日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.2, pp.176-179, 2006 (Released:2006-12-26)

参考文献数

16

被引用文献数

15 47

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Interannual fluctuations of the convective activity around the Philippines are highly correlated with the east-west gradient of SST between the North Indian Ocean (NIO) and the western North Pacific (WNP). We conducted a set of experiments by use of an atmospheric general circulation model (AGCM) to assess the relative importance of the remote (NIO) versus in situ (WNP) SST anomalies in determining the WNP monsoon rainfall as ocean-to-atmosphere feedback. The solutions indicate that both in situ and remote SST anomalies regulate precipitation around the Philippines in the early summer. This result implies that the WNP monsoon rainfall is sensitive to the spatial distribution of the NIO SST anomalies as well as the in situ anomalies. These physical interpretations suggest further increase of the predictability in the WNP monsoon.