Abstract
摘要:在這個計畫下,我們提出一個4年期研究,名稱為“從歐亞前進非洲的第四紀水文氣候與環境變遷研究”,不僅延續我們正在執行的卓越領航計畫,更開展全新的研究議題。我將領導國內與國際團隊,由歐亞前進非洲,並深入太平洋,全面了解第四紀各區域的水文氣候演變與跟海洋的作用關係。利用高解析的天然碳酸鹽標本地球化學多重代用指標與古地磁學分析,輔以氣候模擬,來瞭解歐亞非近代與第四紀環境氣候變遷及古地磁的動力變化;我們也將著重研究太平洋與大西洋在不同地質時間尺度下對歐亞非三個大陸的氣候動力上扮演的角色。各主題如下:(1) 利用各地洞穴碳酸鹽同位素紀錄及精準鈾釷定年技術,了解亞歐與非洲在近數千年與不同地質時間段下的水文氣候變化,以及其與全球氣候和文明的關聯。我們並在本計畫中首次提出使用日本的洞穴石筍研究東亞冬季季風演變。非洲地區的議題則包含:(i) 西非季風與東非季風在百年到軌道尺度下的變化;(ii) 間熱帶輻合區在非洲不同區域的震盪以及與撒哈拉和薩赫勒的連結;(iii) 氣候變化對於非洲古人類的遷徙的可能影響;以及 (iv) 地中海南北區域跟北非的東西區域之水文氣候相位關係。(2) 以太平洋海洋岩心有孔蟲地化指標分析八十萬年以來的南半球熱帶海溫、降雨及氮循環,並結合陸地碳酸鹽氣候紀錄,探討其與亞洲季風、澳洲季風和海洋及大氣環流在軌道尺度的相互動態關係。(3) 進行洞穴碳酸鹽古地磁學分析,以重建地磁場百年內到千年尺度下的變動過程,並建立全新、高精度的磁性地層年代標尺,解析第四紀地磁場變動與全球尺度環境變化的影響。本前緣研究不僅可以更深入了解亞歐與非洲的環境氣候與全球地磁的變化歷史,在學術領域有所突破,透過領導全球各地區的科學家從事頂尖科研合作,還可以拓展良好的科學外交,更將我國的科研成果與影響力推展到全世界
Abstract: A 4-yr proposal “Quaternary climate and environment changes: From Eurasia to Africa” is requested to extend our current 4-yr SVRP project with new subprojects. In this new phase, we will not only continue working in Eurasia but also extend our vision and study territories to Africa and the Pacific Ocean for an in-depth understanding of contemporary and Quaternary global hydroclimate dynamics. High-resolution multi-proxy geochemical and geomagnetic records of natural carbonates and model simulations will be used to reveals paleoclimate and paleoenvironmental changes and geomagnetic dynamics. Forcings from Pacific and Atlantic and also high latitudes on hydroclimate systems in Eurasia and Africa on different geological time scales will be carefully addressed. The specific topics proposed are shown below. (1) We will generate terrestrial stalagmite isotope records paired with precise U-Th dating to understand paleo-hydroclimate changes in Eurasia and Africa over the recent thousands of years and different geological time windows, and establish their global links, and civilization influences. Comprehensive reconstruction of East Asian winter monsoon evolution will be first-time conducted by using Japanese stalagmites collected from sites facing the Japan Sea. The specific topics in Africa include (i) dynamics of West and East African monsoon on centennial-to-orbital timescales, (ii) regional ITCZ migrations and the relations with Sahara and Sahel, (iii) evaluation of possible climate driven human dispersal and migration in and out of Africa, and (iv) hydroclimatic phase relationship between northern and southern Mediterranean and between western and eastern North Africa. (2) Planktonic foraminifera derived sea surface temperature, salinity, precipitation, and nitrogen isotopes from the western Pacific Ocean will be used to systematically reconstruct the tropical precipitation, paleoceanographic circulation, and nitrogen cycles from the Southern Hemisphere over the past 800 thousand years. The interactions between ocean-atmospheric circulations and East Asian monsoon and Australian monsoon on orbital scale will be revealed. (3) Stalagmite based paleomagnetic records will be built to clarify sub-centennial-to-millennial -scale dynamics of geomagnetic field and precisely calendar Quaternary polarity reversals for approaching new benchmark chronology of magnetostratigraphy. This project can provide an important basis for the formulation of modern and future hazard prevention strategies and policies for the environmental climate change in Taiwan and the whole world. Past hydroclimate studies can also offer information on long-term management of water resources. Besides, close collaboration with international colleagues can facilitate excellent academic diplomacy. Our activities and significant scientific outcomes will also help us to show our nation’s visibility to the world.
Keyword(s)
第四紀
歐亞
非洲
太平洋
古氣候變遷
石筍
地磁
Quaternary
Eurasia
Africa
Pacific
Paleoclimate
Stalagmite
Geomagnetism