Late Quaternary Western Pacific and East Asian Climate Variability---Records and Dynamics

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Project title

Code/計畫編號

NSC96-2611-M019-009

Translated Name/計畫中文名

國際海洋古全球變遷研究---西太平洋與東亞之古氣候---子計畫：晚第四紀西太平洋與東亞氣候變化記錄與動力

Project Coordinator/計畫主持人

Min-Te Chen

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Institute of Earth Sciences

Website

https://www.grb.gov.tw/search/planDetail?id=1455266

Year

2007

Start date/計畫起

01-08-2007

Expected Completion/計畫迄

01-07-2008

Bugetid/研究經費

1672千元

ResearchField/研究領域

海洋科學

本計畫為國科會整合型計畫“國際海洋古全球變遷研究-西太平洋與東亞的古氣候综合研究(IMAGES-Paleoclimate of the Western Pacific and East Asia) ”之子計畫。本計畫將分析IMAGES 2005年西太平洋暖池航次在所羅門海(MD052925) 與巴布亞-新幾内亞東南外海(MD052928)所探取的高沈積速率沈積物岩心，以瞭解西赤道太平洋晚第四紀氣候變化型式與控制機制。本計畫將分析岩心 MD052925氧同位素第13-15階的多重海水表面溫度代用指標：1.浮游有孔蟲化石群組合與轉換函數推估之古海水表面溫度；2.浮游有孔蟲殻體鎂/鈣比；3.烯酮類不飽合度dMD052925岩心研究將利用多重古海水表面溫度指標重建本區晚第四紀的全年平均古海水表面溫度與季節性變化，並利用同岩心的浮游有孔蟲氧穩定同位素與古海水表面溫度資料推算古海水表面鹽度(SSS)變化，並可與本計畫前期研究所完成東赤道太平洋岩心ODP1240同時段的SST資料對比。本計畫亦將分析位於西太平洋暖池南緣的岩心MD052928的陸源有機生物指標，如長鏈狀正烷類、醇、酸，與陸地植物木質素巨分子等最近二十萬年的記錄，以推測巴布亞-新幾內亞晚第四紀陸地乾燥度與植被種類變遷所反映的區域降雨量變化，並可與相同時間尺度的沖繩海槽岩心MD012404對比，以了解太平洋不同緯度縱向剖面的氣候變化。本研究將整合其他子計畫所產生的氧穩定同位素、AMS14C、古地磁磁場強度等資料建立高解析度岩心年代模式，判別不同岩心記錄所顯示的海水表面溫度與鹽度在軌道力與千年時間尺度變化的週期性及與全球冰川體積變化的時序關係。預期上列工作的完成將有助於瞭解控制西太平洋之表層海洋環境、水文循環、生物生產力、與沈積物來源與分佈變化的環境因子。本研究所產生的西赤道太平洋古海洋記錄將提供分析西太平洋暖池在全球氣候系統變遷中所扮演的角色，與測試於晚第四紀熱帶海洋的長期性似聖嬰-南方振盪循環現象(Long-term El Nino-Southern Oscillation-like Cycles)與熱帶為全球氣候變化發源的假說。本研究所產生的赤道太平洋溫鹽變化記錄，亦將可與本區其它古氣候記錄，例如黃土、洞穴與湖泊沉積物記錄對比，以瞭解本區域海陸氣候變化的聯繫與相關性。 "Funds are requested for a sub-project program in an integrated project of ""International Marine Past Global Change Study-Paleoclimate of the Western Pacific and East Asia"". This sub-project aims to analyze high sedimentation rate marine cores retrieved from an IMAGES cruise of year 2005 for western Pacific warm pool regions. The top priority cores planning for the analyses of this project are core MD052925 taken from the Solomon Seas, and core MD052928 taken from the southeastern margin of the Papua-New Guinea. Multiple sea-surface temperature (SST) proxies including: 1. planktic foraminiferal fauna assemblages and transfer function estimates; 2. planktic foraminifer Mg/Ca; and 3. alkenone undersaturation indices (Uk 37) are proposed to measure on core MD052925, with focusing on reconstructing variability of annual average SST and seasonality pattern of a particular time interval marine isotope stages 13-15. With combined usage of planktic foraminifer oxygen stable isotope and SST data, this project also aims to extract sea-surface salinity (SSS) estimates from MD052925 records, and comparing those with the same type of estimates from an eastern equatorial Pacific core ODP1240 based on previous results. This project also aims to measure terrestrial organic biomarkers from core MD052928 for estimating past aridity and vegetation pattern changes as controlling by regional precipitation variations. The biomarkers include n-alkane, n-alkanols and n-alkanoic acids, and macromolecules derived from terrestrial higher plants such as ligninphenols. The hydrological variation record could be used to compare with that from Okinawa Trough core MD012404, to establish a latitudinal transect of western Pacific climate. With the developments of high-resolution time-stratigraphy of integrated AMS 14C, and geomagnetic intensity time-stratigraphies cooperated with other project investigators, the SST, SSS, and hydrological variations expressed in the western equatorial Pacific will be examined for better understanding the timing or phase relationship between the tropical climate and global ice volume changes over orbital to millennial time scales. These data observations will permit estimating high-resolution temporal patterns of surface ocean environment, hydrological cycles, biological productivity, and sediment distribution pattern in the western Pacific Oceans. The high-resolution records proposed for studying here provide essential information for testing hypotheses that long-term ENSO (El Niño-Southern Oscillation)-like cycles dominated in the tropical Pacific trigger global glacial-interglacial climate changes in the late Quaternary. The paleoclimatic records reconstructed here will be also compared with Chinese loess, stalagmite and lake records for better understanding the land-sea linkage of regional climate in East Asia and Pacific regions in the late Quaternary."

Keyword(s)

古海洋
古氣候
第四紀
西太平洋
東亞
Paleoceanography
Paleoclimatology
Quaternary
Western Pacific
East Asia

DSpace CRIS

Late Quaternary Western Pacific and East Asian Climate Variability---Records and Dynamics

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