Multiple Sst Reconstructions of Tropical Pacific and South China Sea Paleoclimate

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Project title

Code/計畫編號

NSC99-2611-M019-005

Translated Name/計畫中文名

熱帶太平洋與南海之多元海表溫古氣候重建及西北太平洋深水碳酸鈣保存及風成沉積物研究

Project Coordinator/計畫主持人

Min-Te Chen

Funding Organization/主管機關

National Science and Technology Council

Co-Investigator(s)/共同執行人

李孟陽

Department/Unit

Institute of Earth Sciences

Website

https://www.grb.gov.tw/search/planDetail?id=2126539

Year

2010

Start date/計畫起

01-08-2010

Expected Completion/計畫迄

01-07-2011

Bugetid/研究經費

4771千元

ResearchField/研究領域

海洋科學

"地球–太陽軌道參數週期與全球大陸冰川體積變化，及與大氣溫室氣體濃度的交互作用，為最主要的晚第四紀氣候控制因素；然而，這些主要的氣候控制因素尚無法完全解釋在某些特定時段中於西熱帶太平洋所表現的冰期氣候的極端溫暖潮溼現象（例如海洋氧同位素第14階）與自晚全新世以來的氣候逐漸變乾冷的趨勢。為了解這些西熱帶太平洋在晚第四紀所表現的氣候異常現象，本計畫將研究西熱帶太平洋岩心MD052925, MD052928，東赤道太平洋岩心ODP1240，與預定2010年法國研究船Marion Dufresne在南海高沉積速率區將探取的巨型CASQ箱型岩心（10cm x 10cm x 10m），並規畫分析這些岩心標本的高解析度多元海水表面溫度代用指標：浮游有孔蟲化石群轉換函數、烯酮類不飽和度、浮游有孔蟲殼體鎂鈣比、與有機標幟物TXT86，以重建熱帶太平洋海水表面溫度緯度梯度與高解析度全新世氣候變化。本研究初步結果顯示熱帶太平洋在氧同位素第14階時期的海水表面溫度緯度梯度有較大的不對稱性與梯度增加現象（西太平洋變暖與東太洋變冷）–可能與太平洋間熱帶輻合帶遷移與信風帶變化所引起的大規模的表層海洋與水文氣候變化有關。本計畫規畫參與2010年法國研究船Marion Dufresne的南海航次，以獲得在高沉積速率區所探取的巨型箱型岩心，並分析與重建高解析度多元海水表面溫度記錄，以了解自晚全新世以來的氣候逐漸變溼冷的趨勢是否與間熱帶輻合帶遷移與東亞季風變化機制有關。" "Orbital and global continental ice volume variations with interactive effects from changing atmospheric greenhouse gas concentrations have been widely viewed as dominant pacemakers in the late Quaternary climate, however the mechanisms for explaining the abnormally warm and humid conditions during glacial stages (i.e. Marine Isotope Stage, MIS 14) and gradual cool / dry trends since the late Holocene that were characteristic of the western tropical Pacific regions remain to be explained. To address the apparently abnormal change in the western tropical Pacific, this proposal plans to conduct high-resolution multiple sea surface temperature (SST) analyses using marine cores MD052925, MD052928 (western tropical Pacific), ODP Site 1240 (eastern equatorial Pacific), and new Marion Dufresne giant CASQ box cores (10cm x 10 cm x 10m) taken from high sedimentation rate sites in the 2010 South China Sea cruise. Multiple sea surface temperatures (SST) will be estimated by planktic foraminifer fauna transfer function, the alkenones undersaturation index, Mg/Ca ratio in planktic foraminifer shells, and organic biomarker TXT86 for reconstructing the variations of tropical Pacific zonal SST gradients and high resolution Holocene thermal patterns. Initial results suggest a possibly enhanced zonal asymmetry pattern of the tropical Pacific climate, that is, warming in the west and cooling in the east at glacial MIS 14, and imply that a large-scale climatic shifting that may have involved a migration of the Intertropical Convergence Zone (ITCZ) and a change of trade wind patterns in the tropical Pacific, was probably responsible for the hydrographic history of the tropical Pacific. This work is also designed to retrieve and reconstruct high resolution Holocene SST records by participating giant CASQ box coring in 2010 South China Sea Marion Dufresne cruise. The new high-resolution SST records will be used to identify any ITCZ or monsoon amplification mechanism for explaining late Holocene cool/wet climatic trends in the western tropical Pacific."

Keyword(s)

古海洋
古氣候
西太平洋
第四紀
Paleoceanography
Paleoclimate
Western Pacific
Quaternary

DSpace CRIS

Multiple Sst Reconstructions of Tropical Pacific and South China Sea Paleoclimate

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