The dynamics of Holocene monsoon based on meteoric 10Be at Kunlun Pass on the northeastern Qinghai-Tibet Plateau

2021 ◽  
Author(s):  
Peng Chen ◽  
Zhongbo Yu ◽  
Markus Czymzik ◽  
Ala Aldahan ◽  
Jinguo Wang ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Early Holocene ◽  
Tibet Plateau ◽  
The Holocene ◽  
Proxy Records ◽  
Low Levels ◽  
High Level ◽  
Qinghai Tibet Plateau

<p>Multiple proxy records have been used for the understanding of environmental and climate changes during the Holocene. For the first time, we here measure meteoric <sup>10</sup>Be isotope of sediments from a drill core collected at the Kunlun Pass (KP) on the northeastern Qinghai-Tibet Plateau (NETP) to investigate mositure and atmospheric circulation changes during the Holocene. The <sup>10</sup>Be flux suggests relative low levels in the Early Holocene, followed by a sharp increase to high values at around 4 ka BP (4 ka BP = 4000 years before present). Afterwards, the <sup>10</sup>Be flux remains on a high level during the Late Holocene, but decreases slightly towards today. These <sup>10</sup>Be deposition patterns are compared to moisture changes in regions dominated by the Indian Summer Monsoon (ISM), East Asian Summer Monsoon (EASM), and the Westerlies. Different from the gradual changes in monsoon patterns, the <sup>10</sup>Be data reveal low levels during the Early Holocene until ~4 ka BP when an obvious increase was indicated and a relative high level continues to this day, which is relatively more in agreement with patterns of the Westerlies. This finding provides a new evidence for a shift in the dominant pattern of atmospheric circulation at the KP region from a more monsoonal one to one dominated by the Westerlies. Our results improve the understanding of non-stationary interactions and spatial relevance of the EASM, the ISM and the Westerlies on the Qinghai-Tibet Plateau.</p>

scholarly journals The influence of obliquity in the early Holocene Asian summer monsoon

2016 ◽  
Vol 43 (9) ◽  
pp. 4524-4530 ◽  
Author(s):  
Chi-Hua Wu ◽  
Shih-Yu Lee ◽  
John C. H. Chiang ◽  
Huang-Hsiung Hsu
Keyword(s):  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Early Holocene ◽  
Asian Summer

A 15,400-year record of climate variation from a subalpine lacustrine sedimentary sequence in the western Nanling Mountains in South China

2015 ◽  
Vol 84 (2) ◽  
pp. 246-254 ◽  
Author(s):  
Wei Zhong ◽  
Jiayuan Cao ◽  
Jibin Xue ◽  
Jun Ouyang
Keyword(s):  
Asian Summer Monsoon ◽  
Climate Variation ◽  
Study Region ◽  
The Holocene ◽  
Proxy Records ◽  
The North ◽  
Dry Conditions ◽  
Asian Summer ◽  
Nanling Mountains ◽  
The Tropical Pacific

Multi-proxy records of a subalpine lacustrine sequence in Daping Swamp in the western Nanling Mountains provide evidence for exploring climate variability in the past 15,400 yr. Two dry and cool (15,400–14,500 and 13,000–11,000 cal yr BP) and one humid and warm interval (14,500–13,200 cal yr BP), which we correlate to Heinrich Event 1, the Younger Dryas and the Bølling-Allerød event respectively, are revealed. The early Holocene climate (11,000–8000 cal yr BP) was characterized by less humid and warm conditions, suggesting a weaker Asian summer monsoon (ASM) intensity. Our findings indicate that the Holocene optimum occurred between 8000 and 4500 cal yr BP, and the most intensified ASM appears from 8000 to 7000 cal yr BP. After 4500 cal yr BP, climate shifted to relatively cool and dry conditions. We speculate that five short dry and cool events centered at ~ 11,000, 9000, 8400, 6000, and 3500 cal yr BP were linked to the Holocene ice-rafting events detected in the North Atlantic. Migration of the ITCZ, and the oceanic–atmospheric circulations, particularly SST changes in the tropical Pacific may play a pivotal role in climate variation of the study region.

scholarly journals The Asian Summer Monsoon: Teleconnections and Forcing Mechanisms—A Review from Chinese Speleothem δ18O Records

Quaternary ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 26 ◽  
Author(s):  
Zhang ◽  
Brahim ◽  
Li ◽  
Zhao ◽  
Kathayat ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Temporal Distribution ◽  
The Holocene ◽  
North Atlantic Climate ◽  
Asian Summer ◽  
Spatio Temporal ◽  
Forcing Mechanisms ◽  
The Last Two Millennia ◽  
Global Population

Asian summer monsoon (ASM) variability significantly affects hydro-climate, and thus socio-economics, in the East Asian region, where nearly one-third of the global population resides. Over the last two decades, speleothem δ18O records from China have been utilized to reconstruct ASM variability and its underlying forcing mechanisms on orbital to seasonal timescales. Here, we use the Speleothem Isotopes Synthesis and Analysis database (SISAL_v1) to present an overview of hydro-climate variability related to the ASM during three periods: the late Pleistocene, the Holocene, and the last two millennia. We highlight the possible global teleconnections and forcing mechanisms of the ASM on different timescales. The longest composite stalagmite δ18O record over the past 640 kyr BP from the region demonstrates that ASM variability on orbital timescales is dominated by the 23 kyr precessional cycles, which are in phase with Northern Hemisphere summer insolation (NHSI). During the last glacial, millennial changes in the intensity of the ASM appear to be controlled by North Atlantic climate and oceanic feedbacks. During the Holocene, changes in ASM intensity were primarily controlled by NHSI. However, the spatio-temporal distribution of monsoon rain belts may vary with changes in ASM intensity on decadal to millennial timescales.

Late Pleistocene−Holocene flood history, flood-sediment provenance and human imprints from the upper Indus River catchment, Ladakh Himalaya

2021 ◽  
Author(s):  
Choudhurimayum Pankaj Sharma ◽  
Poonam Chahal ◽  
Anil Kumar ◽  
Saurabh Singhal ◽  
YP Sundriyal ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Phase Relationship ◽  
Human Migration ◽  
Sediment Provenance ◽  
Indus River ◽  
The Holocene ◽  
Extreme Floods ◽  
Ladakh Himalaya ◽  
Extreme Flood

The Indus River, originating from Manasarovar Lake in Tibet, runs along the Indus Tsangpo suture zone in Ladakh which separates the Tethyan Himalaya in the south from the Karakoram zone to the north. Due to the barriers created by the Pir-Panjal ranges and the High Himalaya, Ladakh is located in a rain shadow zone of the Indian summer monsoon (ISM) making it a high-altitude desert. Occasional catastrophic hydrological events are known to endanger lives and properties of people residing there. Evidence of such events in the recent geologic past that are larger in magnitude than modern occurrences is preserved along the channels. Detailed investigation of these archives is imperative to expand our knowledge of extreme floods that rarely occur on the human timescale. Understanding the frequency, distribution, and forcing mechanisms of past extreme floods of this region is crucial to examine whether the causal agents are regional, global, or both on long timescales. We studied the Holocene extreme flood history of the Upper Indus catchment in Ladakh using slackwater deposits (SWDs) preserved along the Indus and Zanskar Rivers. SWDs here are composed of stacks of sand-silt couplets deposited rapidly during large flooding events in areas where a sharp reduction of flow velocity is caused by local geomorphic conditions. Each couplet represents a flood, the age of which is constrained using optically stimulated luminescence for sand and accelerator mass spectrometry and liquid scintillation counter 14C for charcoal specks from hearths. The study suggests occurrence of large floods during phases of strengthened ISM when the monsoon penetrated into arid Ladakh. Comparison with flood records of rivers draining other regions of the Himalaya and those influenced by the East Asian summer monsoon (EASM) indicates asynchronicity with the Western Himalaya that confirms the existing anti-phase relationship of the ISM-EASM that occurred in the Holocene. Detrital zircon provenance analysis indicates that sediment transportation along the Zanskar River is more efficient than the main Indus channel during extreme floods. Post−Last Glacial Maximum human migration, during warm and wet climatic conditions, into the arid upper Indus catchment is revealed from hearths found within the SWDs.

scholarly journals The Eurasian ice sheet reinforces the East Asian summer monsoon during the interglacial 500 000 years ago

2008 ◽  
Vol 4 (2) ◽  
pp. 79-90 ◽  
Author(s):  
◽  
A. Berger ◽  
E. Driesschaert ◽  
H. Goosse ◽  
M. F. Loutre ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Ice Core ◽  
Ice Sheet ◽  
The Tibetan Plateau ◽  
Three Dimension ◽  
Proxy Records ◽  
Asian Summer

Abstract. Deep-sea and ice-core records show that interglacial periods were overall less "warm" before about 420 000 years ago than after, with relatively higher ice volume and lower greenhouse gases concentration. This is particularly the case for the interglacial Marine Isotope Stage 13 which occurred about 500 000 years ago. However, by contrast, the loess and other proxy records from China suggest an exceptionally active East Asian summer monsoon during this interglacial. A three-dimension Earth system Model of Intermediate complexity was used to understand this seeming paradox. The astronomical forcing and the remnant ice sheets present in Eurasia and North America were taken into account in a series of sensitivity experiments. Expectedly, the seasonal contrast is larger and the East Asian summer monsoon is reinforced compared to Pre-Industrial time when Northern Hemisphere summer is at perihelion. Surprisingly, the presence of the Eurasian ice sheet was found to reinforce monsoon, too, through a south-eastwards perturbation planetary wave. The trajectory of this wave is influenced by the Tibetan plateau.

scholarly journals Climate in continental interior Asia during the longest interglacial of the past 500 000 years: the new MIS 11 records from Lake Baikal, SE Siberia

2010 ◽  
Vol 6 (1) ◽  
pp. 31-48 ◽  
Author(s):  
A. A. Prokopenko ◽  
E. V. Bezrukova ◽  
G. K. Khursevich ◽  
E. P. Solotchina ◽  
M. I. Kuzmin ◽  
...  
Keyword(s):  
Lake Baikal ◽  
Regional Climate ◽  
The Holocene ◽  
Proxy Records ◽  
Peak Structure ◽  
Depositional Settings ◽  
Taiga Forest ◽  
Autochthonous Organic Matter ◽  
Study Sites ◽  
High Level

Abstract. A synthesis of paleoclimate responses from Lake Baikal during the MIS 11 interglacial is presented based on proxy records from two drill sites 245 km apart. BDP-99 is located in vicinity of the delta of the major Baikal tributary, whereas the BDP-96 site represents hemipelagic setting distant from riverine influence. The comparison of thicknesses of interglacial intervals in these contrasting depositional settings confirms the extended ca. 33-kyr duration of the MIS 11 interglacial. The new BDP-99 diatom biostratigraphic record matches that of the BDP-96-2 holostratotype and thus allows establishing establishes robust correlation between the records on the same orbitally-tuned timescale. The first detailed MIS 11 palynological record from the BDP-99 drill core indicates the dominance of boreal conifer (taiga) forest vegetation in the Baikal region throughout the MIS 11 interglacial, since at least 424 ka till ca. 396 ka. The interval ca. 420–405 ka stands out as a "conifer optimum" with abundant Abies sibirica, indicative of climate significantly warmer and less continental than today. The closest Baikal analog to this type of vegetation in the history of the current Holocene interglacial is at ca. 9–7 ka. The warm conifer phase lasted for ca. 15 kyr during MIS 11 interrupted by two millennial-scale cooling episodes at ca. 411–410 and 405–404 ka. Reconstructed annual precipitation of 450–550 mm/yr during the MIS 11 interglacial is by ca. 100 mm higher than during the Holocene; regional climate was less continental with warmer mean temperatures both in summer and in winter. At both drill sites, the two-peak structure of the MIS 11 diatom abundance profiles reflects the orbital signature of precession in the interglacial paleoclimate record of continental Eurasia. MIS 11 interglacial was characterized by the sustained high level of primary production and accumulation of autochthonous organic matter at both study sites. The responses of paleoclimate-sensitive indices in the mineralogy of the MIS 11 sediments in BDP-96-2 are consistent with those during the Holocene. Illitization of secondary clay minerals in the Baikal watershed was an important process, but it appears to have been subdued during the first half of the MIS 11, apparently due to elevated humidity and muted seasonality of regional climate.

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