Late Holocene hydroclimatic variations and possible forcing mechanisms over the eastern Central Asia

Hydroclimatic variations over the eastern Central Asia are highly sensitive to changes in hemispheric-scale atmospheric circulation systems. To fully understand the long-term variability and relationship between hydroclimate and atmospheric circulation system, we present a high-resolution lascustrin...

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Bibliographic Details
Published in:Science China Earth Sciences
Main Authors: Lan, Jianghu, Xu, Hai, Yu, Keke, Sheng, Enguo, Zhou, Kangen, Wang, Tianli, Ye, Yuanda, Yan, Dongna, Wu, Huixian, Cheng, Peng, Abuliezi, Waili, Tan, Liangcheng
Format: Report
Language:English
Published: SCIENCE PRESS 2019
Subjects:
Geology
Lake Sayram
Hydroclimatic variation
Late Holocene
Mid-latitude Westerlies
North Atlantic Oscillation index
Geosciences
Multidisciplinary
NORTH-ATLANTIC CLIMATE
RADIOCARBON AGE CALIBRATION
CENTRAL TIAN-SHAN
ARID CENTRAL-ASIA
ICE-AGE
ORGANIC-MATTER
BOSTEN LAKE
ENVIRONMENTAL-CHANGES
LACUSTRINE SEDIMENTS
MOISTURE VARIATIONS
North Atlantic
North Atlantic oscillation
Online Access:http://ir.gig.ac.cn/handle/344008/49754
https://doi.org/10.1007/s11430-018-9240-x
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Summary:Hydroclimatic variations over the eastern Central Asia are highly sensitive to changes in hemispheric-scale atmospheric circulation systems. To fully understand the long-term variability and relationship between hydroclimate and atmospheric circulation system, we present a high-resolution lascustrine record of late Holocene hydroclimate from Lake Sayram, Central Tianshan Mountains, China, based on the total organic carbon, total nitrogen, and carbonate contents, carbon/nitrogen ratios, and grain size. Our results reveal four periods of substantially increased precipitation at the interval of 4000-3780, 3590-3210, 2800-2160, and 890-280 cal yr BP, and one period of slightly increased precipitation from 1700-1370 cal yr BP. These wetter periods broadly coincide with those identified in other records from the mid-latitude Westerlies-dominated eastern Central Asia, including the northern Tibetan Plateau. As such, a similar hydroclimatic pattern existed over this entire region during the late Holocene. Based on a close similarity of our record with reconstruction of North Atlantic Oscillation indices and solar irradiance, we propose that decreased solar irradiance and southern migration of the entire circum-North Atlantic circulation system, particularly the main pathway of the mid-latitude Westerlies, significantly influenced hydroclimate in eastern Central Asia during the late Holocene. Finally, the inferred precipitation at Lake Sayram has increased markedly over the past 100 years, although this potential future changes in hydroclimate in Central Asia need for further investigation.

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