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2. Coupled atmosphere-ice-ocean dynamics during Heinrich Stadial 2

Author

Dong, Xiyu, Kathayat, Gayatri, Rasmussen, Sune O, Svensson, Anders, Severinghaus, Jeffrey P, Li, Hanying, Sinha, Ashish, Xu, Yao, Zhang, Haiwei, Shi, Zhengguo, Cai, Yanjun, Pérez-Mejías, Carlos, Baker, Jonathan, Zhao, Jingyao, Spötl, Christoph, Columbu, Andrea, Ning, Youfeng, Stríkis, Nicolás M, Chen, Shitao, Wang, Xianfeng, Gupta, Anil K, Dutt, Som, Zhang, Fan, Cruz, Francisco W, An, Zhisheng, Lawrence Edwards, R, and Cheng, Hai

Subjects
Earth Sciences, Physical Geography and Environmental Geoscience, Geology, Climate Action
Abstract

Our understanding of climate dynamics during millennial-scale events is incomplete, partially due to the lack of their precise phase analyses under various boundary conditions. Here we present nine speleothem oxygen-isotope records from mid-to-low-latitude monsoon regimes with sub-centennial age precision and multi-annual resolution, spanning the Heinrich Stadial 2 (HS2) - a millennial-scale event that occurred at the Last Glacial Maximum. Our data suggests that the Greenland and Antarctic ice-core chronologies require +320- and +400-year adjustments, respectively, supported by extant volcanic evidence and radiocarbon ages. Our chronological framework shows a synchronous HS2 onset globally. Our records precisely characterize a centennial-scale abrupt "tropical atmospheric seesaw" superimposed on the conventional "bipolar seesaw" at the beginning of HS2, implying a unique response/feedback from low-latitude hydroclimate. Together with our observation of an early South American monsoon shift at the HS2 termination, we suggest a more active role of low-latitude hydroclimate dynamics underlying millennial events than previously thought.

Published
2022

3. Timing and structure of the Younger Dryas event and its underlying climate dynamics

Author

Cheng, Hai, Zhang, Haiwei, Spötl, Christoph, Baker, Jonathan, Sinha, Ashish, Li, Hanying, Bartolomé, Miguel, Moreno, Ana, Kathayat, Gayatri, Zhao, Jingyao, Dong, Xiyu, Li, Youwei, Ning, Youfeng, Jia, Xue, Zong, Baoyun, Brahim, Yassine Ait, Pérez-Mejías, Carlos, Cai, Yanjun, Novello, Valdir F, Cruz, Francisco W, Severinghaus, Jeffrey P, An, Zhisheng, and Edwards, R Lawrence

Subjects
Climate Action, Younger Dryas, timing, structure, event phasing, climate dynamics
Abstract

The Younger Dryas (YD), arguably the most widely studied millennial-scale extreme climate event, was characterized by diverse hydroclimate shifts globally and severe cooling at high northern latitudes that abruptly punctuated the warming trend from the last glacial to the present interglacial. To date, a precise understanding of its trigger, propagation, and termination remains elusive. Here, we present speleothem oxygen-isotope data that, in concert with other proxy records, allow us to quantify the timing of the YD onset and termination at an unprecedented subcentennial temporal precision across the North Atlantic, Asian Monsoon-Westerlies, and South American Monsoon regions. Our analysis suggests that the onsets of YD in the North Atlantic (12,870 ± 30 B.P.) and the Asian Monsoon-Westerlies region are essentially synchronous within a few decades and lead the onset in Antarctica, implying a north-to-south climate signal propagation via both atmospheric (decadal-time scale) and oceanic (centennial-time scale) processes, similar to the Dansgaard-Oeschger events during the last glacial period. In contrast, the YD termination may have started first in Antarctica at ∼11,900 B.P., or perhaps even earlier in the western tropical Pacific, followed by the North Atlantic between ∼11,700 ± 40 and 11,610 ± 40 B.P. These observations suggest that the initial YD termination might have originated in the Southern Hemisphere and/or the tropical Pacific, indicating a Southern Hemisphere/tropics to North Atlantic-Asian Monsoon-Westerlies directionality of climatic recovery.

Published
2020

6. Milankovitch theory and monsoon

Author

Cheng, Hai, Li, Hanying, Sha, Lijuan, Sinha, Ashish, Shi, Zhengguo, Yin, Qiuzhen, Lu, Zhengyao, Zhao, Debo, Cai, Yanjun, Hu, Yongyun, Hao, Qingzhen, Tian, Jun, Kathayat, Gayatri, Dong, Xiyu, Zhao, Jingyao, and Zhang, Haiwei

Published
2022
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14. Onset and termination of Heinrich Stadial 4 and the underlying climate dynamics

Author

Cheng, Hai, Xu, Yao, Dong, Xiyu, Zhao, Jingyao, Li, Hanying, Baker, Jonathan, Sinha, Ashish, Spötl, Christoph, Zhang, Haiwei, Du, Wenjing, Zong, Baoyun, Jia, Xue, Kathayat, Gayatri, Liu, Dianbing, Cai, Yanjun, Wang, Xianfeng, Strikis, Nicolás M., Cruz, Francisco W., Auler, Augusto S., Gupta, Anil K., Singh, Raj Kumar, Jaglan, Sonu, Dutt, Som, Liu, Zhengyu, and Edwards, R. Lawrence

Published
2021
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18. Protracted Indian monsoon droughts of the past millennium and their societal impacts

Author

Kathayat, Gayatri, primary, Sinha, Ashish, additional, Breitenbach, Sebastian F. M., additional, Tan, Liangcheng, additional, Spötl, Christoph, additional, Li, Hanying, additional, Dong, Xiyu, additional, Zhang, Haiwei, additional, Ning, Youfeng, additional, Allan, Robert J., additional, Damodaran, Vinita, additional, Edwards, R. Lawrence, additional, and Cheng, Hai, additional

Published
2022
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20. The Asian monsoon over the past 640,000 years and ice age terminations

Author

Cheng, Hai, Edwards, R. Lawrence, Sinha, Ashish, Spotl, Christoph, Yi, Liang, Chen, Shitao, Kelly, Megan, Kathayat, Gayatri, Wang, Xianfeng, Li, Xianglei, Kong, Xinggong, Wang, Yongjin, Ning, Youfeng, and Zhang, Haiwei

Subjects
Paleoclimatology -- Research, Meteorological research, Monsoons -- Natural history, Caves -- Natural history, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Oxygen isotope records from Chinese caves characterize changes in both the Asian monsoon and global climate. Here, using our new speleothem data, we extend the Chinese record to cover the full uranium/thorium dating range, that is, the past 640,00o years. The record's length and temporal precision allow us to test the idea that insolation changes caused by the Earth's precession drove the terminations of each of the last seven ice ages as well as the millennia-long intervals of reduced monsoon rainfall associated with each of the terminations. On the basis of our record's timing, the terminations are separated by four or five precession cycles, supporting the idea that the '100,000-year' ice age cycle is an average of discrete numbers of precession cycles. Furthermore, the suborbital component of monsoon rainfall variability exhibits power in both the precession and obliquity bands, and is nearly in anti-phase with summer boreal insolation. These observations indicate that insolation, in part, sets the pace of the occurrence of millennial-scale events, including those associated with terminations and 'unfinished terminations'., The seasonal cycle of solar heating over Asia gives rise to the Asian monsoon (AM), a vast system of overturning atmospheric circulation that transports heat and moisture during boreal summer [...]

Published
2016
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21. Milankovitch theory and monsoon

Author

UCL - SST/ELI/ELIC - Earth & Climate, Cheng, Hai, Li, Hanying, Sha, Lijuan, Sinha, Ashish, Shi, Zhengguo, Yin, Qiuzhen, Lu, Zhengyao, Zhao, Debo, Cai, Yanjun, Hu, Yongyun, Hao, Qingzhen, Tian, Jun, Kathayat, Gayatri, Dong, Xiyu, Zhao, Jingyao, Zhang, Haiwei, UCL - SST/ELI/ELIC - Earth & Climate, Cheng, Hai, Li, Hanying, Sha, Lijuan, Sinha, Ashish, Shi, Zhengguo, Yin, Qiuzhen, Lu, Zhengyao, Zhao, Debo, Cai, Yanjun, Hu, Yongyun, Hao, Qingzhen, Tian, Jun, Kathayat, Gayatri, Dong, Xiyu, Zhao, Jingyao, and Zhang, Haiwei

Abstract

The widely accepted “Milankovitch theory” explains insolation-induced waxing and waning of the ice sheets and their effect on the global climate on orbital timescales. In the past half century, however, the theory has often come under scrutiny, especially regarding its “100-ka problem.” Another drawback, but the one that has received less attention, is the “monsoon problem,” which pertains to the exclusion of monsoon dynamics in classic Milankovitch theory even though the monsoon prevails over the vast low-latitude (∼30° N to ∼30° S) region that covers half of the Earth's surface and receives the bulk of solar radiation. In this review, we discuss the major issues with the current form of Milankovitch theory and the progress made at the research forefront. We suggest shifting the emphasis from the ultimate outcomes of the ice volume to the causal relationship between changes in northern high-latitude insolation and ice age termination events (or ice sheet melting rate) to help reconcile the classic “100-ka problem.” We discuss the discrepancies associated with the characterization of monsoon dynamics, particularly the so-called “sea-land precession-phase paradox” and the “Chinese 100-ka problem.” We suggest that many of these discrepancies are superficial and can be resolved by applying a holistic “monsoon system science” approach. Finally, we propose blending the conventional Kutzbach orbital monsoon hypothesis, which calls for summer insolation forcing of monsoons, with Milankovitch theory to formulate a combined “Milankovitch-Kutzbach hypothesis” that can potentially explain the dual nature of orbital hydrodynamics of the ice sheet and monsoon systems, as well as their interplays and respective relationships with the northern high-latitude insolation and inter-tropical insolation differential.

Published
2022

22. Coupled atmosphere-ice-ocean dynamics during Heinrich Stadial 2

Author

Dong, Xinyu, Kathayat, Gayatri, Rasmussen, Sune Olander, Svensson, Anders, Severinghaus, J.P., Li, Hanying, Sinha, Ashish, Xu, Yao, Zhang, H., Shi, Zhengguo, Cai, Yanjun, Pérez-Mejías, Carlos, Baker, J., Zhao, J., Spötl, Christoph, Columbu, Andrea, Ning, Youfeng, Stríkis, Nicolás M., Chen, S., Wang, X., Gupta, A., Dutt, Som, Zhang, F., Cruz, Francisco W., Cheng, H., Dong, Xinyu, Kathayat, Gayatri, Rasmussen, Sune Olander, Svensson, Anders, Severinghaus, J.P., Li, Hanying, Sinha, Ashish, Xu, Yao, Zhang, H., Shi, Zhengguo, Cai, Yanjun, Pérez-Mejías, Carlos, Baker, J., Zhao, J., Spötl, Christoph, Columbu, Andrea, Ning, Youfeng, Stríkis, Nicolás M., Chen, S., Wang, X., Gupta, A., Dutt, Som, Zhang, F., Cruz, Francisco W., and Cheng, H.

Published
2022

24. Indian summer monsoon and winter Total Solar Irradiance signals in the tree‐ring δ18O from foothills of High Asia, northern Pakistan.

Author

Li, Qiang, Liu, Yu, Sinha, Ashish, Kathayat, Gayatri, Duan, Xiangyu, Liu, Ruoshi, Xu, Chenxi, Song, Huiming, Fang, Congxi, Siddiqui, Muhammad Faheem, and Cheng, Hai

Subjects
TREE-rings, WATER vapor transport, FOOTHILLS, MONSOONS, OXYGEN isotopes, ATMOSPHERIC water vapor measurement
Abstract

A tree‐ring stable oxygen isotope (δ18O) chronology was developed for the past 171 years by four Abies pindrow trees growing in southwest foothills of High Asia, northern Pakistan, which is correlated with observed and modelled δ18O of precipitation in Islamabad over the instrumental period. The averaged tree‐ring δ18O chronology is significantly negative correlated with local (r = −.651, p <.001, n = 38) and regional (r = −.664, p <.001, n = 65) summer precipitation variations. Analysis of vertically integrated water vapour flux and surface wind field suggests that the sampling site is located at the northern limit of the Indian summer monsoon (ISM). Our tree‐ring δ18O series is significantly (p <.001, n = 143) negatively correlated with observed Homogenous India rainfall, All Indian rainfall, Core‐Monsoon India rainfall and Northwest India rainfall. This is the first detected ISM signal from tree‐ring δ18O over northern Pakistan. Several ISM‐related paleoclimate proxies, including three stalagmites δ18O series (Sahiya cave, Jhumar cave and Qunf cave) and a tree‐ring δ18O series (Manali), show consistent variability and a correlation coefficient of.566 (p <.001, n = 165) with our tree‐ring δ18O, suggesting that a combination of multiple proxies may be potentially useful to understand the full perspective of ISM before instrumental era. In addition, we found that the satellite‐observed winter Total Solar Irradiance exerts influence on the tree‐ring δ18O variation (r =.643, p <.001, n = 38), which may be linked to runoff of the Indus River and ISM precipitation. [ABSTRACT FROM AUTHOR]

Published
2023
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26. Collapse of the Liangzhu and other Neolithic cultures in the lower Yangtze region in response to climate change

Author

Zhang, Haiwei, primary, Cheng, Hai, additional, Sinha, Ashish, additional, Spötl, Christoph, additional, Cai, Yanjun, additional, Liu, Bin, additional, Kathayat, Gayatri, additional, Li, Hanying, additional, Tian, Ye, additional, Li, Youwei, additional, Zhao, Jingyao, additional, Sha, Lijuan, additional, Lu, Jiayu, additional, Meng, Binglin, additional, Niu, Xiaowen, additional, Dong, Xiyu, additional, Liang, Zeyuan, additional, Zong, Baoyun, additional, Ning, Youfeng, additional, Lan, Jianghu, additional, and Edwards, R. Lawrence, additional

Published
2021
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27. Evaluating model outputs using integrated global speleothem records of climate change since the last glacial

Author

Comas-Bru, Laia, Harrison, Sandy P., Werner, Martin, Rehfeld, Kira, Scroxton, Nick, Veiga-Pires, Cristina, Ahmad, Syed Masood, Brahim, Yassine Ait, Mozhdehi, Sahar Amirnezhad, Arienzo, Monica, Atsawawaranunt, Kamolphat, Baker, Andy, Braun, Kerstin, Breitenbach, Sebastian, Burstyn, Yuval, Chawchai, Sakonvan, Columbu, Andrea, Deininger, Michael, Demeny, Attila, Dixon, Bronwyn, Hatvani, Istvan Gabor, Hu, Jun, Kaushal, Nikita, Kern, Zoltan, Labuhn, Inga, Lachniet, Matthew S., Lechleitner, Franziska A., Lorrey, Andrew, Markowska, Monika, Nehme, Carole, Novello, Valdir F., Oster, Jessica, Perez-Mejias, Carlos, Pickering, Robyn, Sekhon, Natasha, Wang, Xianfeng, Warken, Sophie, Atkinson, Tim, Ayalon, Avner, Baldini, James, Bar-Matthews, Miryam, Bernal, Juan Pablo, Boch, Ronny, Borsato, Andrea, Boyd, Meighan, Brierley, Chris, Cai, Yanjun, Carolin, Stacy, Cheng, Hai, Constantin, Silviu, Couchoud, Isabelle, Cruz, Francisco, Denniston, Rhawn, Dragusin, Virgil, Duan, Wuhui, Ersek, Vasile, Finné, Martin, Fleitmann, Dominik, Fohlmeister, Jens, Frappier, Amy, Genty, Dominique, Holzkamper, Steffen, Hopley, Philip, Johnston, Vanessa, Kathayat, Gayatri, Keenan-Jones, Duncan, Koltai, Gabriella, Li, Ting-Yong, Lone, Mahjoor Ahmad, Luetscher, Marc, Mattey, Dave, Moreno, Ana, Moseley, Gina, Psomiadis, David, Ruan, Jiaoyang, Scholz, Denis, Sha, Lijuan, Smith, Andrew Christopher, Strikis, Nicolas, Treble, Pauline, Unal-Imer, Ezgi, Vaks, Anton, Vansteenberge, Stef, Voarintsoa, Ny Riavo G., Wong, Corinne, Wortham, Barbara, Wurtzel, Jennifer, Zhang, Haiwei, Voarintsoa, Ny Riavo, Earth Observatory of Singapore, Comas-Bru L., Harrison S.P., Werner M., Rehfeld K., Scroxton N., Veiga-Pires C., Ahmad S.M., Brahim Y.A., Mozhdehi S.A., Arienzo M., Atsawawaranunt K., Baker A., Braun K., Breitenbach S., Burstyn Y., Chawchai S., Columbu A., Deininger M., Demeny A., Dixon B., Hatvani I.G., Hu J., Kaushal N., Kern Z., Labuhn I., Lachniet M.S., Lechleitner F.A., Lorrey A., Markowska M., Nehme C., Novello V.F., Oster J., Perez-Mejias C., Pickering R., Sekhon N., Wang X., Warken S., Atkinson T., Ayalon A., Baldini J., Bar-Matthews M., Bernal J.P., Boch R., Borsato A., Boyd M., Brierley C., Cai Y., Carolin S., Cheng H., Constantin S., Couchoud I., Cruz F., Denniston R., Dragusin V., Duan W., Ersek V., Finne M., Fleitmann D., Fohlmeister J., Frappier A., Genty D., Holzkamper S., Hopley P., Johnston V., Kathayat G., Keenan-Jones D., Koltai G., Li T.-Y., Lone M.A., Luetscher M., Mattey D., Moreno A., Moseley G., Psomiadis D., Ruan J., Scholz D., Sha L., Smith A.C., Strikis N., Treble P., Unal-Imer E., Vaks A., Vansteenberge S., Voarintsoa N.R.G., Wong C., Wortham B., Wurtzel J., and Zhang H.

Subjects
010506 paleontology, Climate Research, 010504 meteorology & atmospheric sciences, δ18O, lcsh:Environmental protection, Climate Change, Stratigraphy, Speleothem, Climate change, F800, PMIP4 CONTRIBUTION, Geology [Science], 01 natural sciences, Klimatforskning, STABLE-ISOTOPE VARIATIONS, lcsh:Environmental pollution, Time windows, ddc:550, Meteorology & Atmospheric Sciences, lcsh:TD169-171.8, Speleothem Records, GENERAL-CIRCULATION MODEL, ASIAN MONSOON, Glacial period, Geosciences, Multidisciplinary, DELTA-O-18 WATER ISOTOPE, Baseline (configuration management), lcsh:Environmental sciences, 0105 earth and related environmental sciences, lcsh:GE1-350, Global and Planetary Change, geography, Coupled model intercomparison project, Science & Technology, geography.geographical_feature_category, Paleontology, Geology, GROWTH FREQUENCY VARIATIONS, NORTH-ATLANTIC, OXYGEN-ISOTOPE, 13. Climate action, Climatology, lcsh:TD172-193.5, Physical Sciences, Spatial ecology, Environmental science, Institut für Geowissenschaften, ATMOSPHERIC CIRCULATION, HIGH-RESOLUTION
Abstract

Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data-model comparisons. Here, we illustrate this using 456 globally distributed speleothem delta O-18 records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data-model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model's ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on delta O-18 values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices. European Geosciences Union - W2017/413; Irish Centre for Research in Applied Geosciences (iCRAG); European Association of Geochemistry (Early Career Ambassadors program 2017); Quaternary Research Association UK; Navarino Environmental Observatory, Stockholm University; University College Dublin, Savillex (UK) - SF1428; Ibn Zohr University, Morocco; University of Reading; European Research Council - 694481; Natural Environment Research Council (JPI-Belmont project "PAleao-Constraints on Monsoon Evolution and Dynamics (PACMEDY)"); Geological Survey Ireland - 2017-SC-056; Royal Irish Academy; Deutsche Forschungsgemeinschaft - RE3994/2-1; Past Global Changes (PAGES) programme; info:eu-repo/semantics/publishedVersion

Published
2019

28. Gradual South‐North Climate Transition in the Atlantic Realm Within the Younger Dryas

Author

Zhang, Haiwei, primary, Cheng, Hai, additional, Spötl, Christoph, additional, Zhang, Xu, additional, Cruz, Francisco W., additional, Sinha, Ashish, additional, Auler, Augusto S., additional, Stríkis, Nicolás M., additional, Wang, Xianfeng, additional, Kathayat, Gayatri, additional, Li, Xianglei, additional, Li, Hanying, additional, Pérez‐Mejías, Carlos, additional, Cai, Yanjun, additional, Ning, Youfeng, additional, and Edwards, Richard Lawrence, additional

Published
2021
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29. Timing and structure of the Younger Dryas event and its underlying climate dynamics

Author

National Natural Science Foundation of China, National Science Foundation (US), Cheng, Hai, Zhang, Haiwei, Spötl, Christoph, Baker, Jonathan, Sinha, Ashish, Li, Hanying, Bartolomé, Miguel, Moreno Caballud, Ana, Kathayat, Gayatri, Zhao, Jingyao, Dong, Xiyu, Li, Youwei, Ning, Youfeng, Jia, Xue, Zong, Baoyun, Brahim, Yassine Ait, Pérez-Mejías, Carlos, Cai, Yanjun, Novello, Valdir F., Cruz, Francisco W., Severinghaus, Jeffrey P., An, Zhisheng, Edwards, R. Lawrence, National Natural Science Foundation of China, National Science Foundation (US), Cheng, Hai, Zhang, Haiwei, Spötl, Christoph, Baker, Jonathan, Sinha, Ashish, Li, Hanying, Bartolomé, Miguel, Moreno Caballud, Ana, Kathayat, Gayatri, Zhao, Jingyao, Dong, Xiyu, Li, Youwei, Ning, Youfeng, Jia, Xue, Zong, Baoyun, Brahim, Yassine Ait, Pérez-Mejías, Carlos, Cai, Yanjun, Novello, Valdir F., Cruz, Francisco W., Severinghaus, Jeffrey P., An, Zhisheng, and Edwards, R. Lawrence

Abstract

The Younger Dryas (YD), arguably the most widely studied millennialscale extreme climate event, was characterized by diverse hydroclimate shifts globally and severe cooling at high northern latitudes that abruptly punctuated the warming trend from the last glacial to the present interglacial. To date, a precise understanding of its trigger, propagation, and termination remains elusive. Here, we present speleothem oxygen-isotope data that, in concert with other proxy records, allow us to quantify the timing of the YD onset and termination at an unprecedented subcentennial temporal precision across the North Atlantic, Asian Monsoon-Westerlies, and South American Monsoon regions. Our analysis suggests that the onsets of YD in the North Atlantic (12,870 ± 30 B.P.) and the Asian Monsoon- Westerlies region are essentially synchronous within a few decades and lead the onset in Antarctica, implying a north-to-south climate signal propagation via both atmospheric (decadal-time scale) and oceanic (centennial-time scale) processes, similar to the Dansgaard- Oeschger events during the last glacial period. In contrast, the YD termination may have started first in Antarctica at ~11,900 B.P., or perhaps even earlier in the western tropical Pacific, followed by the North Atlantic between ~11,700 ± 40 and 11,610 ± 40 B.P. These observations suggest that the initial YD termination might have originated in the Southern Hemisphere and/or the tropical Pacific, indicating a Southern Hemisphere/tropics to North Atlantic-Asian Monsoon-Westerlies directionality of climatic recovery.

Published
2020

30. A multimillennial climatic context for the megafaunal extinctions in Madagascar and Mascarene Islands

Author

Li, Hanying, primary, Sinha, Ashish, additional, Anquetil André, Aurèle, additional, Spötl, Christoph, additional, Vonhof, Hubert B., additional, Meunier, Arnaud, additional, Kathayat, Gayatri, additional, Duan, Pengzhen, additional, Voarintsoa, Ny Riavo G., additional, Ning, Youfeng, additional, Biswas, Jayant, additional, Hu, Peng, additional, Li, Xianglei, additional, Sha, Lijuan, additional, Zhao, Jingyao, additional, Edwards, R. Lawrence, additional, and Cheng, Hai, additional

Published
2020
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36. Role of climate in the rise and fall of the Neo-Assyrian Empire

Author

Sinha, Ashish, primary, Kathayat, Gayatri, additional, Weiss, Harvey, additional, Li, Hanying, additional, Cheng, Hai, additional, Reuter, Justin, additional, Schneider, Adam W., additional, Berkelhammer, Max, additional, Adalı, Selim F., additional, Stott, Lowell D., additional, and Edwards, R. Lawrence, additional

Published
2019
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37. Investigating the 8.2 ka event in northwestern Madagascar: insight from data–model comparisons

Author

Voarintsoa, Ny Riavo G, Matero, Ilkka SO, Railsback, L Bruce, Gregoire, Lauren J, Tindall, Julia, Sime, Louise, Cheng, Hai, Edwards, R Lawrence, Brook, George A, Kathayat, Gayatri, Li, Xianglei, Rakotondrazafy, Amos Fety Michel, Razanatseheno, Marie Olga Madison, Voarintsoa, Ny Riavo G, Matero, Ilkka SO, Railsback, L Bruce, Gregoire, Lauren J, Tindall, Julia, Sime, Louise, Cheng, Hai, Edwards, R Lawrence, Brook, George A, Kathayat, Gayatri, Li, Xianglei, Rakotondrazafy, Amos Fety Michel, and Razanatseheno, Marie Olga Madison

Abstract

The 8.2 ka event is a well-known cooling event in the Northern Hemisphere, but is poorly understood in Madagascar. Here, we compare paleoclimate data and outputs from paleoclimate simulations to better understand it. Records from Madagascar suggest two distinct sub-events (8.3 ka and 8.2 ka), that seem to correlate with records from northern high latitude. This could indicate causal relationships via changes in the Atlantic Meridional Overturning Circulation (AMOC) with changes in moisture source's d18O, and changes in the mean position of the Inter-Tropical Convergence Zone (ITCZ), as climate modelling suggests. These two sub-events are also apparent in other terrestrial records, but the climatic signals are different. The prominent 8.2 ka sub-event records a clear antiphase relationship between the northern and southern hemisphere monsoons, whereas such relationship is less evident during the first 8.3 ka sub-event. Data-model comparison have also shown a mismatch between the paleoclimate data and the model outputs, the causes of which are more or less understood and may lie in the proxies, in the model, or in both data and model. Knowing that paleoclimate proxies and climate models produce different sets of variables, further research is needed to improve the data-model comparison approach, so that both paleoclimate data and paleoclimate models will better predict the likely climate status of a region during a specified time in the past with minimal uncertainties.

Published
2019

38. The SISAL database

Author

Atsawawaranunt, Kamolphat, Comas-Bru, Laia, Mozhdehi, Sahar Amirnezhad, Deininger, Michael, Harrison, Sandy P., Baker, Andy, Boyd, Meighan, Kaushal, Nikita, Ahmad, Syed Masood, Brahim, Yassine Ait, Arienzo, Monica, Bajo, Petra, Braun, Kerstin, Burstyn, Yuval, Chawchai, Sakonvan, Duan, Wuhui, Hatvani, Istvan Gabor, Hu, Jun, Kern, Zoltan, Labuhn, Inga, Lachniet, Matthew, Lechleitner, Franziska A., Lorrey, Andrew, Perez-Mejias, Carlos, Pickering, Robyn, Scroxton, Nick, Atkinson, Tim, Ayalon, Avner, Baldini, James, Bar-Matthews, Miriam, Pablo Bernal, Juan, Breitenbach, Sebastian, Boch, Ronny, Borsato, Andrea, Cai, Yanjun, Carolin, Stacy, Cheng, Hai, Columbu, Andrea, Couchoud, Isabelle, Cruz, Francisco, Demeny, Attila, Dominguez-Villar, David, Dragusin, Virgil, Drysdale, Russell, Ersek, Vasile, Finne, Martin, Fleitmann, Dominik, Fohlmeister, Jens Bernd (Dr.), Frappier, Amy, Genty, Dominique, Holzkamper, Steffen, Hopley, Philip, Kathayat, Gayatri, Keenan-Jones, Duncan, Koltai, Gabriella, Luetscher, Marc, Li, Ting-Yong, Lone, Mahjoor Ahmad, Markowska, Monika, Mattey, Dave, McDermott, Frank, Moreno, Ana, Moseley, Gina, Nehme, Carole, Novello, Valdir F., Psomiadis, David, Rehfeld, Kira, Ruan, Jiaoyang, Sekhon, Natasha, Sha, Lijuan, Sholz, Denis, Shopov, Yavor, Smith, Andrew, Strikis, Nicolas, Treble, Pauline, Unal-Imer, Ezgi, Vaks, Anton, Vansteenberge, Stef, Veiga-Pires, Cristina, Voarintsoa, Ny Riavo, Wang, Xianfeng, Wong, Corinne, Wortham, Barbara, Wurtzel, Jennifer, and Zong, Baoyun

Subjects
ddc:550, Institut für Geowissenschaften
Abstract

Stable isotope records from speleothems provide information on past climate changes, most particularly information that can be used to reconstruct past changes in precipitation and atmospheric circulation. These records are increasingly being used to provide "out-of-sample" evaluations of isotope-enabled climate models. SISAL (Speleothem Isotope Synthesis and Analysis) is an international working group of the Past Global Changes (PAGES) project. The working group aims to provide a comprehensive compilation of speleothem isotope records for climate reconstruction and model evaluation. The SISAL database contains data for individual speleothems, grouped by cave system. Stable isotopes of oxygen and carbon (delta O-18, delta C-13) measurements are referenced by distance from the top or bottom of the speleothem. Additional tables provide information on dating, including information on the dates used to construct the original age model and sufficient information to assess the quality of each data set and to erect a standardized chronology across different speleothems. The metadata table provides location information, information on the full range of measurements carried out on each speleothem and information on the cave system that is relevant to the interpretation of the records, as well as citations for both publications and archived data.

Published
2018

39. The SISAL database: a global resource to document oxygen and carbon isotope records from speleothems

Author

Atsawawaranunt, Kamolphat, Comas-Bru, Laia, Amirnezhad Mozhdehi, Sahar, Deininger, Michael, Harrison, Sandy P., Baker, Andy, Boyd, Meighan, Kaushal, Nikita, Ahmad, Syed Masood, Ait Brahim, Yassine, Arienzo, Monica, Bajo, Petra, Braun, Kerstin, Burstyn, Yuval, Chawchai, Sakonvan, Duan, Wuhui, Hatvani, István Gábor, Hu, Jun, Kern, Zoltán, Labuhn, Inga, Lachniet, Matthew, Lechleitner, Franziska A., Lorrey, Andrew, Pérez-Mejías, Carlos, Pickering, Robyn, Scroxton, Nick, Atkinson, Tim, Ayalon, Avner, Baldini, James, Bar-Matthews, Miriam, Bernal, Juan Pablo, Breitenbach, Sebastian, Boch, Ronny, Borsato, Andrea, Cai, Yanjun, Carolin, Stacy, Cheng, Hai, Columbu, Andrea, Couchoud, Isabelle, Cruz, Francisco, Demény, Attila, Domínguez-Villar, David, Drăgusin, Virgil, Drysdale, Russell, Ersek, Vasile, Finné, Martin, Fleitmann, Dominik, Fohlmeister, Jens, Frappier, Amy, Genty, Dominique, Holzkämper, Steffen, Kathayat, Gayatri, Keenan-Jones, Duncan, Koltai, Gabriella, Luetscher, Marc, Li, Ting-Yong, Lone, Mahjoor Ahmad, Markowska, Monika, Mattey, Dave, McDermott, Frank, Moreno, Ana, Moseley, Gina, Nehme, Carole, Novello, Valdir F., Psomiadis, David, Rehfeld, Kirah, Ruan, Jiaoyang, Sekhon, Natasha, Sha, Lijuan, Scholz, Denis, Shopov, Yavor, Strikis, Nicolás, Treble, Pauline, Ünal-İmer, Ezgi, Vaks, Anton, Vansteenberge, Stef, Veiga-Pires, Cristina, Voarintsoa, Ny Riavo, Wang, Xianfeng, Wong, Corinne, Wortham, Barbara, Wurtzel, Jennifer, and Zong, Baoyun

Abstract

Stable isotope records from speleothems provide information on past climate changes, most particularly information that can be used to reconstruct past changes in precipitation and atmospheric circulation. These records are increasingly being used to provide “out-of-sample” evaluations of isotope-enabled climate models. SISAL (Speleothem Isotope Synthesis and Analysis) is an international working group of the Past Global Changes (PAGES) project. The working group aims to provide a comprehensive compilation of speleothem isotope records for climate reconstruction and model evaluation. The SISAL database contains data for individual speleothems, grouped by cave system. Stable isotopes of oxygen and carbon (δ18O, δ13C) measurements are referenced by distance from the top or bottom of the speleothem. Additional tables provide information on dating, including information on the dates used to construct the original age model and sufficient information to assess the quality of each data set and to erect a standardized chronology across different speleothems. The metadata table provides location information, information on the full range of measurements carried out on each speleothem and information on the cave system that is relevant to the interpretation of the records, as well as citations for both publications and archived data. The compiled data are available at http://dx.doi.org/10.17864/1947.147 .

Published
2018

40. Eastern North American climate in phase with fall insolation throughout the last three glacial-interglacial cycles

Author

Cheng, Hai, primary, Springer, Gregory S., additional, Sinha, Ashish, additional, Hardt, Benjamin F., additional, Yi, Liang, additional, Li, Hanying, additional, Tian, Ye, additional, Li, Xianglei, additional, Rowe, Harold D., additional, Kathayat, Gayatri, additional, Ning, Youfeng, additional, and Edwards, R. Lawrence, additional

Published
2019
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41. Investigating the 8.2 ka event in northwestern Madagascar: Insight from data–model comparisons

Author

Voarintsoa, Ny Riavo G., primary, Matero, Ilkka S.O., additional, Railsback, L. Bruce, additional, Gregoire, Lauren J., additional, Tindall, Julia, additional, Sime, Louise, additional, Cheng, Hai, additional, Edwards, R. Lawrence, additional, Brook, George A., additional, Kathayat, Gayatri, additional, Li, Xianglei, additional, Michel Rakotondrazafy, Amos Fety, additional, and Madison Razanatseheno, Marie Olga, additional

Published
2019
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45. Timing and structure of the Younger Dryas event and its underlying climate dynamics.

Author

Hai Cheng, Haiwei Zhanga, Spötl, Christoph, Baker, Jonathan, Sinha, Ashish, Hanying Li, Bartolomé, Miguel, Moreno, Ana, Kathayat, Gayatri, Jingyao Zhao, Xiyu Dong, Youwei Li, Youfeng Ning, Xue Jia, Baoyun Zong, Ait Brahim, Yassine, Pérez-Mejiás, Carlos, Yanjun Cai, Novello, Valdir F., and Cruz, Francisco W.

Subjects
YOUNGER Dryas, GLACIATION, CLIMATOLOGY
Abstract

The Younger Dryas (YD), arguably the most widely studied millennialscale extreme climate event, was characterized by diverse hydroclimate shifts globally and severe cooling at high northern latitudes that abruptly punctuated the warming trend from the last glacial to the present interglacial. To date, a precise understanding of its trigger, propagation, and termination remains elusive. Here, we present speleothem oxygen-isotope data that, in concert with other proxy records, allow us to quantify the timing of the YD onset and termination at an unprecedented subcentennial temporal precision across the North Atlantic, Asian Monsoon-Westerlies, and South American Monsoon regions. Our analysis suggests that the onsets of YD in the North Atlantic (12,870 ± 30 B.P.) and the Asian Monsoon-Westerlies region are essentially synchronous within a few decades and lead the onset in Antarctica, implying a north-to-south climate signal propagation via both atmospheric (decadal-time scale) and oceanic (centennial-time scale) processes, similar to the Dansgaard– Oeschger events during the last glacial period. In contrast, the YD termination may have started first in Antarctica at ∼11,900 B.P., or perhaps even earlier in the western tropical Pacific, followed by the North Atlantic between ∼11,700 ± 40 and 11,610 ± 40 B.P. These observations suggest that the initial YD termination might have originated in the Southern Hemisphere and/or the tropical Pacific, indicating a Southern Hemisphere/tropics to North Atlantic–Asian Monsoon-Westerlies directionality of climatic recovery. [ABSTRACT FROM AUTHOR]

Published
2020
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