Meridional Migrations Of The Intertropical Convergence Zone During The Last Deglaciation In The Timor Sea Detected By Extensive Radiocarbon Dating
Type | Article | ||||||||||||
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Acceptance Date | 2024-02-27 IN PRESS | ||||||||||||
Language | English | ||||||||||||
Author(s) | Nemoto Karin1, 2, Yokoyama Yusuke1, 2, 3, 4, 5, Horiike Satoshi1, Obrochta Stephen P6, Miyairi Yosuke1 | ||||||||||||
Affiliation(s) | 1 : Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8564, Japan 2 : Department of Earth and Planetary Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8033, Japan 3 : Graduate Program on Environmental Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan 4 : Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Natsushimacho 2-15, Yokosuka, Kanagawa 237-0061, Japan 5 : Research School of Physics, The Australian National University, Canberra, ACT, 2601, Australia 6 : Graduate School of International Resource Science, Akita University, 1-1 Tegatagakuenmachi, Akita 010-8502 Japan |
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Source | Radiocarbon (0033-8222) (Cambridge University Press (CUP)) In Press | ||||||||||||
DOI | 10.1017/RDC.2024.13 | ||||||||||||
Keyword(s) | deglaciation, Intertropical Convergence Zone, radiocarbon AMS dating | ||||||||||||
Abstract | At the Intertropical Convergence Zone (ITCZ), the northern and southern Tradewinds converge, and this region is characterized by low atmospheric pressure and high precipitation. The climate in the Timor Sea is characterized by seasonal precipitation changes driven by meridional migrations of the ITCZ and the monsoonal front. The ITCZ shifts in response to changes in the thermal balance between the northern and southern hemispheres. Thus, reconstruction of paleo-precipitation in the Timor Sea is expected to reveal past changes in both regional and global climate, the latter through inference of the ITCZ position. To reconstruct paleo-precipitation in the Timor Sea, we performed extensive radiocarbon analysis on both planktonic foraminifera and total organic carbon (TOC), which is derived from terrestrial and marine sources. Increased precipitation enhances the fraction of relatively old, terrestrial carbon to the core site, which in turn increases the difference between the ages of TOC and planktonic foraminifera. Variations in radiocarbon ages reveal that during northern hemisphere cooling intervals such as Heinrich Stadial 1 and the Younger Dryas, the ITCZ was in a southern position, thus increasing precipitation in the Timor Sea. However, the Timor Sea was dryer during the Bølling–Allerød warming as the ITCZ shifted northward. |
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