A detailed East Asian monsoon history surrounding the ‘Mystery Interval’ derived from three Chinese speleothem records

2014 ◽  
Vol 82 (1) ◽  
pp. 154-163 ◽  
Author(s):  
Weihong Zhang ◽  
Jiangying Wu ◽  
Yi Wang ◽  
Yongjin Wang ◽  
Hai Cheng ◽  
...  
Keyword(s):  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
Global Climate ◽  
East Asian ◽  
Meridional Overturning Circulation ◽  
Last Deglaciation ◽  
Two Phase ◽  
Carbon Cycles ◽  
Global Climate Changes ◽  
Meridional Overturning

AbstractThe ‘Mystery Interval’ (MI, 17.5−14.5 ka) was the first stage of the last deglaciation, a key interval for understanding mechanisms of glacial–interglacial cycles. To elucidate possible causes of the MI, here we present three high-resolution, precisely dated oxygen-isotope records of stalagmites from Qingtian and Hulu Caves in China, reflecting changes in the East Asian summer monsoon (EASM) then. Based on well-established chronologies using precise 230Th dates and annual-band counting results, the two-cave δ18O profiles of ~7-yr resolution match well at decadal timescales. Both of the two-cave records document an abrupt weakening (2‰ of δ18O rise within 20 yr) in the EASM at ~16.1 ka, coinciding with the transition of the two-phased MI reconstructed from New Mexico's Lake Estancia. Our results indicate that the maximum southward displacement of the Intertropical Convergence Zone and associated southward shift of polar jet stream may generate this two-phase feature of the MI during that time. We also discover a linear relationship among decreasing EASM intensity, rising atmospheric CO2 and weakening Atlantic Meridional Overturning Circulation between the MI and Younger Dryas episodes, suggesting a strong coupling of atmospheric/oceanic circulations in response to the millennial-scale forcing, which in turn regulates global climate changes and carbon cycles.

scholarly journals Synchronicity of the East Asian Summer Monsoon variability and Northern Hemisphere climate change since the last deglaciation

2011 ◽  
Vol 7 (3) ◽  
pp. 2159-2192 ◽  
Author(s):  
T. Shinozaki ◽  
M. Uchida ◽  
K. Minoura ◽  
M. Kondo ◽  
S. F. Rella ◽  
...  
Keyword(s):  
North Atlantic ◽  
Climate Changes ◽  
Asian Summer Monsoon ◽  
Global Climate ◽  
East Asian ◽  
Last Deglaciation ◽  
Low Latitude ◽  
Global Climate Changes ◽  
Asian Summer ◽  
The Last Deglaciation

Abstract. Understanding of the mechanism of the East Asian Summer Monsoon (EASM) is required for the prediction of climate change in East Asia in a scenario of modern global warming. In this study, we present high-resolution climate records from peat sediments in Northeast Japan to reconstruct the EASM variability based on peat bulk cellulose δ13C since the last deglaciation. We used a 8.8 m long peat sediment core collected from the Tashiro Bog, Northeast Japan. Based on 42 14C measurements, the core bottom reaches ~15.5 ka. δ13C, accumulation rate and accumulation flux time-series correlate well to Greenland ice core δ18O variability, suggesting that the climate record in Northeast Japan is linked to global climate changes. The δ13C record at Tashiro Bog and other paleo-EASM records at Northeast and Southern China consistently demonstrate that hydrological environments were spatially different in mid-high and mid-low latitude regions over the last 15.5 kyr. During global cooling (warming) periods, mid-high and mid-low latitude regions were characterized by wet (dry) and dry (wet) environments, respectively. We suggest that these climatic patterns are related to the migration of the EASM-related rain belt during global climate changes, as a consequence of variations in intensity and location of both the Intertropical Convergence Zone (ITCZ) and the Western Pacific Subtropical High (STH). The location of the rain belt largely influences the East Asian hydrological environment. Our δ13C time-series are characterized by a 1230 yr throughout the Holocene and a 680 yr periodicity during the early Holocene. The 1230 yr periodicity is in agreement with North Atlantic ice-rafted debris (IRD) events, suggesting a teleconnection between the Northeast Japan and the North Atlantic during the Holocene. In addition, it is the first evidence that the Bond events were recorded in terrestrial sediment in Japan. On the other hand, the 680 yr periodicity between 10.0 and 8.0 kyr is consistent with a prominent 649 yr solar activity cycle, suggesting that solar activity affected EASM precipitation during the Hypsithermal, when orbital-scale solar insolation was at a maximum in the Northern Hemisphere.

scholarly journals Tectonic and climatic drivers of Asian monsoon evolution

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
James R. Thomson ◽  
Philip B. Holden ◽  
Pallavi Anand ◽  
Neil R. Edwards ◽  
Cécile A. Porchier ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Asian Monsoon ◽  
Monsoon Rainfall ◽  
East Asian Monsoon ◽  
East Asian ◽  
Meridional Overturning Circulation ◽  
Great Debate ◽  
Climatic Drivers ◽  
Meridional Overturning

AbstractAsian Monsoon rainfall supports the livelihood of billions of people, yet the relative importance of different drivers remains an issue of great debate. Here, we present 30 million-year model-based reconstructions of Indian summer monsoon and South East Asian monsoon rainfall at millennial resolution. We show that precession is the dominant direct driver of orbital variability, although variability on obliquity timescales is driven through the ice sheets. Orographic development dominated the evolution of the South East Asian monsoon, but Indian summer monsoon evolution involved a complex mix of contributions from orography (39%), precession (25%), atmospheric CO2 (21%), ice-sheet state (5%) and ocean gateways (5%). Prior to 15 Ma, the Indian summer monsoon was broadly stable, albeit with substantial orbital variability. From 15 Ma to 5 Ma, strengthening was driven by a combination of orography and glaciation, while closure of the Panama gateway provided the prerequisite for the modern Indian summer monsoon state through a strengthened Atlantic meridional overturning circulation.

Orbital- and suborbital-scale changes in the East Asian summer monsoon since the last deglaciation

The Holocene ◽  
2018 ◽  
Vol 28 (8) ◽  
pp. 1216-1224 ◽  
Author(s):  
Junfeng Li ◽  
Xingqi Liu
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Northern China ◽  
Meridional Overturning Circulation ◽  
Last Deglaciation ◽  
Climatic Fluctuations ◽  
Asian Summer ◽  
The Last Deglaciation

The variability of the East Asian summer monsoon (EASM) has far-reaching effects on the global climate system and the environment, and full understanding of the variability and dynamics of the EASM contributes to predictions of its future behavior. Here, we present a well-dated mineralogical and total organic carbon record from a saline inland lake in northern China which provides a robust archive of the EASM evolution since 16.0 cal. ka BP. Our record reveals a series of rapid and frequent millennial-scale climatic fluctuations during the last deglaciation; these fluctuations are documented by changes in the abundances of mirabilite, bloedite, and gypsum, which appear to record the Oldest Dryas, the Bølling-Allerød warm period, and the Younger Dryas. The peak EASM moisture occurred in the early and middle Holocene, which was punctuated by a prominent and abrupt weak monsoon interval that occurred synchronously with the 8.2 cal. ka BP cold event. This moisture maximum was terminated at 6.9–5.9 cal. ka BP by a warm-dry event marked by the deposition of gaylussite. Subsequently, the EASM gradually weakened over the late Holocene. The EASM moisture patterns reconstructed from Anguli-nuur Lake display good consistency with records from northern China, as revealed by a regional comparison; moreover, the recorded changes are synchronous with those of the Indian summer monsoon moisture patterns, as revealed by a comparison with the stalagmite records of southern China. Our reconstruction shows that the EASM has responded broadly to Northern Hemisphere summer insolation forcing on orbital time scales since the last deglaciation; thus, insolation is the primary factor that controls regional hydrological variations in the Asian monsoonal domain. The suborbital-scale events are related to the Atlantic meridional overturning circulation, and a slowdown of this circulation would lead to a southward shift of the intertropical convergence zone and a weakening of the EASM.

scholarly journals A late Pleistocene dataset of Agulhas Current variability

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Margit H. Simon ◽  
Martin Ziegler ◽  
Stephen Barker ◽  
Marcel T. J. van der Meer ◽  
Stefan Schouten ◽  
...  
Keyword(s):  
Global Climate ◽  
Current System ◽  
Meridional Overturning Circulation ◽  
Glacial Cycle ◽  
Data Set ◽  
Agulhas Current ◽  
Global Climate Changes ◽  
The Past ◽  
Age Model ◽  
Meridional Overturning

Abstract The interocean transfer of thermocline water between the Indian and the Atlantic Oceans known as ‘Agulhas leakage’ is of global significance as it influences the Atlantic Meridional Overturning Circulation (AMOC) on different time scales. Variability in the Agulhas Current regime is key in shaping hydroclimate on the adjacent coastal areas of the African continent today as well as during past climates. However, the lack of long, continuous records from the proximal Agulhas Current region dating beyond the last glacial cycle prevents elucidation of its role in regional and wider global climate changes. This is the first continuous record of hydrographic variability (SST; δ18Osw) from the Agulhas Current core region spanning the past 270,000 years. The data set is analytical sound and provides a solid age model. As such, it can be used by paleoclimate scientists, archaeologists, and climate modelers to evaluate, for example, linkages between the Agulhas Current system and AMOC dynamics, as well as connections between ocean heat transport and Southern African climate change in the past and its impact on human evolution.

scholarly journals The 4.2 ka event in East Asian monsoon region, precisely reconstructed by multi-proxies of stalagmite

2021 ◽  
Author(s):  
Chao-Jun Chen ◽  
Dao-Xian Yuan ◽  
Jun-Yun Li ◽  
Xian-Feng Wang ◽  
Hai Cheng ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
Global Climate ◽  
Meridional Overturning Circulation ◽  
Driving Mechanism ◽  
Chinese History ◽  
Asian Monsoon Region ◽  
The North ◽  
Opposite Change

Abstract. The 4.2 ka event is one of the most salient features of global climate change in the mid-late Holocene and influenced on the evolution of ancient civilizations. Although a lot of paleoclimate reconstructions have focused on it, the detailed structure and driving mechanism of the 4.2 ka event is still unclear. In this study, the variation of Asian summer monsoon (ASM) during 5000–3000 yr BP was reconstructed by using high-precision U-Th dating (average resolution of 7 yr) and multi-proxies (δ13C, δ18O, Ba / Ca, Sr / Ca, Mg / Ca) of stalagmite YK1306 from Yangkou Cave in southwestern China. The results showed that that the ASM weakened and precipitation decreased during 4600–4330 yr BP and 4070–3700 yr BP. During 4330–4070 yr BP, the ASM became strong, and precipitation increased. The multi-proxies variation of YK1306 showed a weak-strong-weak structure of the ASM during the 4.2 ka event, which reappeared in different geologic records. However, westerlies and Australian-Indian summer monsoon (AISM) both showed the opposite change pattern (strong-weak-strong) with the ASM. This was resulted by the different phases of North Atlantic Oscillation (NAO) on a centennial scale, which regulated by the Atlantic Meridional Overturning Circulation (AMOC). In positive NAO-like, the strength of Azores high and westerly wind restrained the intensity of ASM. Thus, the ASM and the Middle East regions experienced bimodal drought and increased dust flux from the north in both regions during the 4.2 ka event. The strengthened meridional winds in the westerlies-dominated climatic regime (WDCR) lead more water vapor from the Indian Ocean and Arabian Sea transporting to in the WDCR, and subsequently increases precipitation in the WDCR. Meanwhile, the weakening of the AMOC results in the southward migration of the Intertropical Convergence Zone (ITCZ) and strengthens the AISM in the southern Hemisphere, finally results in the opposite change of the AISM contrast to the ASM. In addition, the strong ASM in the era of the Chinese Xia Dynasty maybe produce frequent ancient floods, which led to the decline of Longshan and Liangzhu cultures. The weakening of the ASM after 4070 yr BP contributed to the successful regulation of the ancient floodwaters by Dayu in Chinese history. Therefore, it is maybe credible that the official age for the establishment of the Xia Dynasty in 4070 yr BP. Benefit from the comprehensive comparison and analysis based on the unprecedented high-precise chronology, high-resolution and multi-proxy's stalagmite records, this study not only detailed described the evolution of the ASM during the 4.2 ka event, but also is conducive to verify the age of the first dynasty of China (the Xia Dynasty), and the legend of Dayu.

scholarly journals Linking Holocene East Asian monsoon variability to solar forcing and ENSO activity: Multi-proxy evidence from a peatland in Northeastern China

The Holocene ◽  
2021 ◽  
pp. 095968362199466
Author(s):  
Nannan Li ◽  
Arash Sharifi ◽  
Frank M Chambers ◽  
Yong Ge ◽  
Nathalie Dubois ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Northeastern China ◽  
Solar Irradiation ◽  
Enso Events ◽  
Monsoon Area ◽  
Wavelet Coherency ◽  
Cross Wavelet

High-resolution proxy-based paleoenvironmental records derived from peatlands provide important insights into climate changes over centennial to millennial timescales. In this study, we present a composite climatic index (CCI) for the Hani peatland from northeastern China, based on an innovative combination of pollen-spore, phytolith, and grain size data. We use the CCI to reconstruct variations of the East Asian summer monsoon (EASM) intensity during the Holocene. This is accomplished with complete ensemble empirical mode decomposition (CEEMD), REDFIT, and cross-wavelet coherency analysis to reveal the periodicities (frequencies) of the multi-proxy derived CCI sequences and to assess potential external forcing of the EASM. The results showed that periodicities of ca. 300–350, 475, 600, 1075, and 1875 years were present in the Hani CCI sequence. Those periodicities are consistent with previously published periodicities in East Asia, indicating they are a product of external climate controls over an extensive region, rather than random variations caused by peatland-specific factors. Cross-wavelet coherency analysis between the decomposed CCI components and past solar activity reconstructions suggests that variations of solar irradiation are most likely responsible for the cyclic characteristics at 500-year frequency. We propose a conceptual model to interpret how the sun regulates the monsoon climate via coupling with oceanic and atmospheric circulations. It seems that slight solar irradiation changes can be amplified by coupling with ENSO events, which result in a significant impact on the regional climate in the East Asian monsoon area.

scholarly journals Changes in Paleovegetation and Paleoclimate in China Since the Late Middle Pleistocene: A Case Study of the Dajiuhu Basin

2021 ◽  
Vol 13 (9) ◽  
pp. 4848
Author(s):  
Liwei Wu ◽  
Xinling Li ◽  
Qinghai Xu ◽  
Manyue Li ◽  
Qiufeng Zheng ◽  
...  
Keyword(s):  
Grain Size ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Central China ◽  
Middle Pleistocene ◽  
Pollen Record ◽  
The Difference ◽  
Late Middle Pleistocene

The East Asian monsoon system is an important part of global atmospheric circulation; however, records of the East Asian monsoon from different regions exhibit different evolutionary rhythms. Here, we show a high-resolution record of grain size and pollen data from a lacustrine sediment core of Dajiuhu Lake in Shennongjia, Hubei Province, China, in order to reconstruct the paleovegetation and paleoeclimate evolution of the Dajiuhu Basin since the late Middle Pleistocene (~237.9 ka to the present). The results show that grain size and pollen record of the core DJH-2 are consistent with the δ18O record of stalagmites from Sanbao Cave in the same area, which is closely related to the changes of insolation at the precessional (~20-kyr) scale in the Northern Hemisphere. This is different from the records of the Asian summer monsoon recorded in the Loess Plateau of North China, which exhibited dominant 100-kyr change cyclicities. We suggest that the difference between paleoclimatic records from North and South China is closely related to the east–west-oriented mountain ranges of the Qinling Mountains in central China that blocked weakened East Asia summer monsoons across the mountains during glacial periods.

scholarly journals The potential of Hudson Valley glacial floods to drive abrupt climate change

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Simon Pendleton ◽  
Alan Condron ◽  
Jeffrey Donnelly
Keyword(s):  
Meridional Overturning Circulation ◽  
Cold Period ◽  
Flood Events ◽  
Last Deglaciation ◽  
Hudson Valley ◽  
Periodic Input ◽  
Input Location ◽  
Meridional Overturning ◽  
Climatic Cooling ◽  
Relationship Of

AbstractThe periodic input of meltwater into the ocean from a retreating Laurentide Ice Sheet is often hypothesized to have weakened the Atlantic meridional overturning circulation (AMOC) and triggered several cold periods during the last deglaciation (21,000 to 8,000 years before present). Here, we use a numerical model to investigate whether the Intra-Allerød Cold Period was triggered by the drainage of Glacial Lake Iroquois, ~13,300 years ago. Performing a large suite of experiments with various combinations of single and successive, short (1 month) and long (1 year) duration flood events, we were unable to find any significant weakening of the AMOC. This result suggests that although the Hudson Valley floods occurred close to the beginning of the Intra-Allerød Cold Period, they were unlikely the sole cause. Our results have implications for re-evaluating the relationship of meltwater flood events (past and future) to periods of climatic cooling, particularly with regards to flood input location, volume, frequency, and duration.

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