ACG06-01

会場:101A

時間:5 月 26 日 11:00-11:20

インドネシア海大陸の速い水循環： 「AM ラジオ」仮説
Quick water cycle over the Indonesian maritime continent: An ”AM radio” hypothesis
山中 大学 1∗YAMANAKA, Manabu D.1∗
11

海洋研究開発機構大気海洋相互作用研究分野／神戸大学大学院理学研究科
DCOP, JAMSTEC / DP-GSS, Kobe U

平成 17〜21 年度「地球観測システム構築推進プラン (JEPP)」による海大陸レーダー網 (HARIMAU) 構築および 21〜25 年度「地球規模課題対応国際科学技術協力 (SATREPS)」による海大陸最先端研究拠点 (MCCOE) 構築により、海風水蒸気輸送、雲・降雨、河川水輸送の全てが日周期変化することが示された。
従ってインドネシア海大陸域の水循環は極めて速く、大規模現象や経年・季節内変動に伴って（日周期海陸風循環強度を通じて）雨量等の増幅はするが、日周期は基本的に維持される。この様相は「AM ラジオ」に似ている。その意味では、中緯度のような総観規模現象の連続的な観測・予測よりも、地域ごとの観測や毎日新たに（何度も）予測する方が適している。
キーワード: インドネシア海大陸, 雲対流, 水循環, 日周期, HARIMAU レーダー網, SATREPS-MCCOE
Keywords: Indonesian maritime continent, cloud convection, water cycle, diurnal cycle, HARIMAU, MCCOE

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ACG06-02

会場:101A

時間:5 月 26 日 11:20-11:35

MJO role on Intraseasonal variation of stable isotope of Precipitation in Indonesia Maritime Continent
MJO role on Intraseasonal variation of stable isotope of Precipitation in Indonesia Maritime Continent
BELGAMAN, Halda aditya1∗ ; ICHIYANAGI, Kimpei1 ; TANOUE, Masahiro2 ; SUWARMAN, Rusmawan3 ;YOSHIMURA, Kei4 ; MORI, Shuichi5 ; KURITA, Naoyuki6
BELGAMAN, Halda aditya1∗ ; ICHIYANAGI, Kimpei1 ; TANOUE, Masahiro2 ; SUWARMAN, Rusmawan3 ;YOSHIMURA, Kei4 ; MORI, Shuichi5 ; KURITA, Naoyuki61GSST Kumamoto Univ., 2 School of Engineering, The University of Tokyo, 3 Bandung Institute of Technology, 4 AORI, TheUniv. of Tokyo, 5 JAMSTEC, Japan, 6 Nagoya Univ.
1GSST Kumamoto Univ., 2 School of Engineering, The University of Tokyo, 3 Bandung Institute of Technology, 4 AORI, TheUniv. of Tokyo, 5 JAMSTEC, Japan, 6 Nagoya Univ.
MJO (Madden-Julian Oscillation) is one of the disturbances for Asian Monsoon in the Maritime Continent Area. Intraseasonalvariability of precipitation in the Indonesia Maritime Continent (IMC) is mainly due to The Madden-Julian Oscillation (MJO),
cold surge, or other synoptic scale disturbance. This study examined the relationship between MJO and stable isotope in precipitation over the IMC. Observation and simulation model data from isotope circulation model was used. From 2001 - 2009, 10main MJO events were detected and 6 of the event occurred at Boreal Winter season (Asian Monsoon). Temporal and spatial
analysis from simulated stable isotopes model reveals that isotopic variation is correlated to MJO event in different phase fordifferent stations. Generally, δ 18 O in precipitation became lighter in most observation station at phase 3, 4 and 5 at western partof IMC, and phase 4, 5, and 6 at north east part of IMC. Spatial distribution of δ 18 O in precipitation for each MJO phase showthat mainly MJO governed δ 18 O variability in intraseasonal timescale for IMC area. Further investigation showed clear signalof MJO in δ 18 O was observed at Bukit Tinggi (GAW) station only; it is confirmed with result from Isotope Circulation Model(ICM). When MJO is in active phase (enhanced) precipitation in western part of IMC, precipitable water was came from IndianOcean and South IMC Ocean.
キーワード: asian monsoon disturbance, stable isotope, Madden Julian Oscillation, moisture transport analysis
Keywords: asian monsoon disturbance, stable isotope, Madden Julian Oscillation, moisture transport analysis

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会場:101A

時間:5 月 26 日 11:35-11:50

南シナ海夏季モンスーンオンセットの年々変動および 10 年規模変動に対する海洋の役割
Relative role of the ocean for interannual and decadal variations in summer monsoon
onset over the South China Sea
今川 新 2∗ ; 樋口 篤志 1
IMAKAWA, Shin2∗ ; HIGUCHI, Atsushi1
1
1

千葉大学 環境リモートセンシング研究センター, 2 千葉大学 大学院理学研究科
Center for Environmental Remote Sensing (CEReS), Chiba University, 2 Graduate School of Science, Chiba University

In this study, we reveal a difference of mechanisms with interannual variation a 15-years variation in the South China Sea
Summer Monsoon (SCSSM) onset. The SCSSM onset occurs in active convections over the South China Sea (SCS), whenconvections are active over the Philippine Sea (PS). Variations in the SCSSM onset are affect by the variations in the convective
activities over SCS and PS. The increase in the sea surface temperature (SST) over the Western Pacific in recent years causes
the more active convection over the PS, therefore the SCSSM onset is advanced in 15-years variation as already pointed out by
Kajikawa and Wang (2012).
Moreover, we elucidate the relation between the SCSSM onset date anomaly and aggregated SST over the SCS from Januaryto March. The correlation is good between the SCSSM onset date anomaly and the aggregated SST over SCS, while a poor
relation founds between the 15-years variation oriented signal in onset date and the SST in SCS. When SCSSM onset date isdelayed, the aggregated SST in SCS has tend to high temperature. On the other hand, the correlation is good between the 15-years
variation in the SCSSM onset date and the aggregated SST over the PS. The SST anomalies over the SCS are influenced by thefrequencies and strength of cold surges during boreal winter. Strong and longer cold surges bring the lower SST over the SCS.
The cold surges are brought about the anticyclone over the Eastern Eurasian continent. An arctic sea-ice decline instigates thehigh-pressure deviation over the Eurasian Continent. Then relatively lower land surface temperature in middle latitude, and bringthe cold surge over the SCS.

キーワード: 夏季モンスーン, オンセット, 南シナ海
Keywords: summer monsoon, onset, South China Sea

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ACG06-04

会場:101A

時間:5 月 26 日 11:50-12:05

フィリピンにおける降雨と大気循環の気候学的季節変化
Climatological seasonal changes of rainfall and circulation in the Philippines
松本 淳 1∗ ; Nguyen-Le Dzung1 ; Villafuerte Marcelino II2
MATSUMOTO, Jun1∗ ; NGUYEN-LE, Dzung1 ; VILLAFUERTE, Marcelino ii211

首都大学東京 地理学教室, 2 フィリピン宇宙気象局
Department of Geogreaphy, Tokyo Metropolitan University, 2 PAGASA, Philippines

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 highwas 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 theAsian Human Resource Fund of the Tokyo Metropolitan Government.

キーワード: モンスーン, 季節変化, モンスーン開始, モンスーン撤退, 雨季
Keywords: monsoon, seasonal changes, monsoon onset, monsoon withdrawal, rainy season

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ACG06-05

会場:101A

時間:5 月 26 日 12:05-12:25

Long-term Regional Precipitation Disparity in Northwestern China and Its Driving ForcesLong-term Regional Precipitation Disparity in Northwestern China and Its Driving Forces
LEE, Harry F.1∗
LEE, Harry F.1∗
11

Department of Geography, The University of Hong Kong
Department of Geography, The University of Hong Kong

Precipitation in Northwestern China (NW China) is characterized by salient regional differences. Yet, the long-term regional
precipitation disparity in NW China still remains insufficiently-explored. In the present study, we base on historical documentation to derive the fine-grained precipitation indices of two macro regions in NW China between AD580 and 1979 to (1)determine the multi-decadal to centennial regional precipitation disparity in NW China; and (2) find the major driving forces
behind it. Wavelet analysis is applied. Our results show that there is significant regional discrepancy of precipitation change
in NW China over extended period. Besides, the association between the regional precipitation disparity in NW China andvarious modes of atmospheric circulation (Asian Summer Monsoon, Arctic Oscillation, Pacific Decadal Oscillation, and North
Atlantic Oscillation) is significant and characterized by a regime shift during the transition from the warm episode to the Little
Ice Age in the 14th century. Most importantly, the ∼180 to 240 year cycle of the El Niño-Southern Oscillation is found to be themost prominent pacemaker of regional precipitation disparity in NW China at the long-term temporal scales. Our findings help
to demonstrate which atmospheric circulation is primarily responsible for the long-term regional precipitation disparity in NW
China, which may have important implications for water resource management there.
キーワード: precipitation, moisture, atmospheric circulations, Asian Summer Monsoon, El Nino-Southern Oscillation, Northwestern China
Keywords: precipitation, moisture, atmospheric circulations, Asian Summer Monsoon, El Nino-Southern Oscillation, Northwestern China

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