Japan Geoscience Union Meeting 2015

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International Session (Oral)

Symbol A (Atmospheric and Hydrospheric Sciences) » A-CG Complex & General

[A-CG06] Asian monsoon hydroclimate

Tue. May 26, 2015 11:00 AM - 12:45 PM 101A (1F)

Convener:*Jun Matsumoto(Deaprtment of Geography, Tokyo Metropolitan University), Taikan Oki(Institute of Industrial Science, The University of Tokyo), Atsushi Higuchi(Center for Environmental Remote Sensing (CEReS), Chiba University, Japan), Shinjiro Kanae(School of Engineering, Tokyo Institute of Technology), Hiroshi Takahashi(Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University), Chair:Atsushi Higuchi(Center for Environmental Remote Sensing (CEReS), Chiba University, Japan)

11:50 AM - 12:05 PM

[ACG06-04] Climatological seasonal changes of rainfall and circulation in the Philippines

*Jun MATSUMOTO1, Dzung Nguyen-Le1, Marcelino II Villafuerte2 (1.Department of Geogreaphy, Tokyo Metropolitan University, 2.PAGASA, Philippines)

Keywords:monsoon, seasonal changes, monsoon onset, monsoon withdrawal, rainy season

Climatological seasonal changes of rainfall and lower tropospheric circulation in the Philippines were analyzed by utilizing 5-day mean TRMM 3B-42 and station rainfall data provided by PAGASA, and ERA-Interim wind data for the period 1998-2013. In particular, climatological onset and withdrawal processes of the southwest monsoon were investigated.

It was found that the onset of southwest monsoon occurred abruptly in mid-May. It started from the north in the Philippines both in rainfall and wind, which showed a peculiar feature in this region. After the onset, anti-cyclonic flow from the Pacific high was predominant, and it changed into cyclonic flow in mid-June. Easterlies still remained in the south until early July, afterwards SW monsoon covered the whole country and enhanced from late July.

Southwest monsoon began to retreat from the north in mid- September, and fully retreated from the southern tip of the Philippines in late October.

Acknowledgment: Part of this study was supported by The JSPS KAKENHI, The GRENE program of the MEXT, and the Asian Human Resource Fund of the Tokyo Metropolitan Government.