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Yuan S, Chiang HW, Liu G, Bijaksana S, He S, Jiang X, Imran AM, Wicaksono SA, Wang X. Reply to Lu et al.: Robust Intertropical Convergence Zone variability reconstructed from Maritime Continent speleothem δ 18O records. Proc Natl Acad Sci U S A 2024; 121:e2409163121. [PMID: 38913884 DOI: 10.1073/pnas.2409163121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/26/2024] Open
Affiliation(s)
- Shufang Yuan
- Earth Observatory of Singapore, Nanyang Technological University, Singapore 639798, Singapore
- Asian School of Environment, Nanyang Technological University, Singapore 639798, Singapore
| | - Hong-Wei Chiang
- Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan
| | - Guangxin Liu
- Department of Atmospheric Science, Yunnan University, Kunming 650500, China
| | - Satria Bijaksana
- Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung 40132, Indonesia
| | - Shaoneng He
- Earth Observatory of Singapore, Nanyang Technological University, Singapore 639798, Singapore
- Asian School of Environment, Nanyang Technological University, Singapore 639798, Singapore
| | - Xiuyang Jiang
- School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
| | - Andi M Imran
- Department of Geological Engineering, Hasanuddin University, Makassar 90245, Indonesia
| | - Satrio A Wicaksono
- Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI 02912
| | - Xianfeng Wang
- Earth Observatory of Singapore, Nanyang Technological University, Singapore 639798, Singapore
- Asian School of Environment, Nanyang Technological University, Singapore 639798, Singapore
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Li X, Zhou Y, Han Z, Yuan X, Yi S, Zeng Y, Qin L, Lu M, Lu H. Loess deposits in the low latitudes of East Asia reveal the ~20-kyr precipitation cycle. Nat Commun 2024; 15:1023. [PMID: 38310099 PMCID: PMC10838313 DOI: 10.1038/s41467-024-45379-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 01/18/2024] [Indexed: 02/05/2024] Open
Abstract
The cycle of precipitation change is key to understanding the driving mechanism of the East Asian summer monsoon (EASM). However, the dominant cycles of EASM precipitation revealed by different proxy indicators are inconsistent, leading to the "Chinese 100 kyr problem". In this study, we examine a high-resolution, approximately 350,000-year record from a low-latitude loess profile in China. Our analyses show that variations in the ratio of dithionite-citrate-bicarbonate extractable iron to total iron are dominated by the ~20-kyr cycle, reflecting changes in precipitation. In contrast, magnetic susceptibility varies with the ~100-kyr cycle and may be mainly controlled by temperature-induced redox processes or precipitation-induced signal smoothing. Our results suggest that changes in the EASM, as indicated by precipitation in this region, are mainly forced by precession-dominated insolation variations, and that precipitation and temperature may have varied with different cycles over the past ~350,000 years.
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Affiliation(s)
- Xusheng Li
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China
| | - Yuwen Zhou
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China
| | - Zhiyong Han
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China.
| | - Xiaokang Yuan
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China
| | - Shuangwen Yi
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China
| | - Yuqiang Zeng
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China
| | - Lisha Qin
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China
| | - Ming Lu
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China
| | - Huayu Lu
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China
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Fohlmeister J, Sekhon N, Columbu A, Vettoretti G, Weitzel N, Rehfeld K, Veiga-Pires C, Ben-Yami M, Marwan N, Boers N. Global reorganization of atmospheric circulation during Dansgaard-Oeschger cycles. Proc Natl Acad Sci U S A 2023; 120:e2302283120. [PMID: 37639590 PMCID: PMC10483664 DOI: 10.1073/pnas.2302283120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/26/2023] [Indexed: 08/31/2023] Open
Abstract
Ice core records from Greenland provide evidence for multiple abrupt cold-warm-cold events recurring at millennial time scales during the last glacial interval. Although climate variations resembling Dansgaard-Oeschger (DO) oscillations have been identified in climate archives across the globe, our understanding of the climate and ecosystem impacts of the Greenland warming events in lower latitudes remains incomplete. Here, we investigate the influence of DO-cold-to-warm transitions on the global atmospheric circulation pattern. We comprehensively analyze δ18O changes during DO transitions in a globally distributed dataset of speleothems and set those in context with simulations of a comprehensive high-resolution climate model featuring internal millennial-scale variations of similar magnitude. Across the globe, speleothem δ18O signals and model results indicate consistent large-scale changes in precipitation amount, moisture source, or seasonality of precipitation associated with the DO transitions, in agreement with northward shifts of the Hadley circulation. Furthermore, we identify a decreasing trend in the amplitude of DO transitions with increasing distances from the North Atlantic region. This provides quantitative observational evidence for previous suggestions of the North Atlantic region being the focal point for these archetypes of past abrupt climate changes.
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Affiliation(s)
- Jens Fohlmeister
- Potsdam Institute for Climate Impact Research, 14473Potsdam, Germany
| | - Natasha Sekhon
- Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI02912
- Institute at Brown for Environment and Society, Brown University, Providence, RI02912
| | - Andrea Columbu
- Department of Earth Sciences, University of Pisa, 56126Pisa, Italy
| | - Guido Vettoretti
- Physics of Ice, Climate and Earth, Niels Bohr Institute, University of Copenhagen, 2200Copenhagen, Denmark
| | - Nils Weitzel
- Department of Geosciences, University of Tübingen, 72076Tübingen, Germany
- Institute of Environmental Physics, Heidelberg University, 69120Heidelberg, Germany
| | - Kira Rehfeld
- Department of Geosciences, University of Tübingen, 72076Tübingen, Germany
- Institute of Environmental Physics, Heidelberg University, 69120Heidelberg, Germany
- Department of Physics, University of Tübingen, 72076Tübingen, Germany
| | - Cristina Veiga-Pires
- Centre for Marine and Environmental Research, Faculty of Sciences and Technology, Universidade do Algarve, Campus de Gambelas, 8005-139Faro, Portugal
| | - Maya Ben-Yami
- Potsdam Institute for Climate Impact Research, 14473Potsdam, Germany
- Earth System Modelling, School of Engineering & Design, Technical University of Munich, Munich80333, Germany
| | - Norbert Marwan
- Potsdam Institute for Climate Impact Research, 14473Potsdam, Germany
| | - Niklas Boers
- Potsdam Institute for Climate Impact Research, 14473Potsdam, Germany
- Earth System Modelling, School of Engineering & Design, Technical University of Munich, Munich80333, Germany
- Global Systems Institute, University of Exeter, ExeterEX4 4QF, UK
- Department of Mathematics, University of Exeter, ExeterEX4 4QF, UK
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Tharammal T, Bala G, Nusbaumer JM. Sources of water vapor and their effects on water isotopes in precipitation in the Indian monsoon region: a model-based assessment. Sci Rep 2023; 13:708. [PMID: 36639545 PMCID: PMC9839761 DOI: 10.1038/s41598-023-27905-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Climate records of ratios of stable water isotopes of oxygen (δ18O) are used to reconstruct the past Indian monsoon precipitation. Identifying the sources of water vapor is important in understanding the role of monsoonal circulation in the δ18O values, to aid in monsoon reconstructions. Here, using an isotope-enabled Earth system model, we estimate the contributions of oceanic and terrestrial water vapor sources to two major precipitation seasons in India-the Southwest monsoon and the Northeast monsoon, and their effects on the δ18O in precipitation (δ18Op). We find that the two monsoon seasons have different dominant sources of water vapor because of the reversal in atmospheric circulation. While Indian Ocean regions, Arabian Sea, and recycling are the major sources of the Southwest monsoon precipitation, North Pacific Ocean and recycling are two crucial sources of Northeast monsoon precipitation. The δ18Op of the Southwest monsoon precipitation is determined by contributions from the Indian Ocean sources and recycling. Despite reduced precipitation, more negative δ18Op values are simulated in the Northeast monsoon season due to larger negative δ18Op contributions from the North Pacific. Our results imply that changes in atmospheric circulation and water vapor sources in past climates can influence climate reconstructions using δ18O.
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Affiliation(s)
- Thejna Tharammal
- grid.34980.360000 0001 0482 5067Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore, India ,grid.34980.360000 0001 0482 5067Present Address: Interdisciplinary Centre for Water Research, Indian Institute of Science, Bangalore, India
| | - Govindasamy Bala
- grid.34980.360000 0001 0482 5067Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore, India
| | - Jesse M. Nusbaumer
- grid.57828.300000 0004 0637 9680National Center for Atmospheric Research, Boulder, CO USA
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Late Pleistocene human paleoecology in the highland savanna ecosystem of mainland Southeast Asia. Sci Rep 2021; 11:16756. [PMID: 34408215 PMCID: PMC8373907 DOI: 10.1038/s41598-021-96260-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/06/2021] [Indexed: 02/07/2023] Open
Abstract
The late Pleistocene settlement of highland settings in mainland Southeast Asia by Homo sapiens has challenged our species's ability to occupy mountainous landscapes that acted as physical barriers to the expansion into lower-latitude Sunda islands during sea-level lowstands. Tham Lod Rockshelter in highland Pang Mapha (northwestern Thailand), dated between 34,000 and 12,000 years ago, has yielded evidence of Hoabinhian lithic assemblages and natural resource use by hunter-gatherer societies. To understand the process of early settlements of highland areas, we measured stable carbon and oxygen isotope compositions of Tham Lod human and faunal tooth enamel. Our assessment of the stable carbon isotope results suggests long-term opportunistic behavior among hunter-gatherers in foraging on a variety of food items in a mosaic environment and/or inhabiting an open forest edge during the terminal Pleistocene. This study reinforces the higher-latitude and -altitude extension of a forest-grassland mosaic ecosystem or savanna corridor (farther north into northwestern Thailand), which facilitated the dispersal of hunter-gatherers across mountainous areas and possibly allowed for consistency in a human subsistence strategy and Hoabinhian technology in the highlands of mainland Southeast Asia over a 20,000-year span near the end of the Pleistocene.
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