Arid Central Asia (ACA) lies on a major climatic boundary between the mid-latitude westerlies and the northwestern limit of the Asian summer monsoon, yet only a few high-quality reconstructions exist for its climate history. Here we calibrate a new organic geochemical proxy for lake temperature, and present a 45-yr-resolution temperature record from Hurleg Lake at the eastern margin of the ACA in the northern Tibetan Plateau. Combination with other proxy data from the same samples reveals a distinct warm-dry climate association throughout the record, which contrasts with the warm-wet association found in the Asian monsoon region. This indicates that the climatic boundary between the westerly and the monsoon regimes has remained roughly in the same place throughout the Holocene, at least near our study site. Six millennial-scale cold events are found within the past 9000. yr, which approximately coincide with previously documented events of northern high-latitude cooling and tropical drought. This suggests a connection between the North Atlantic and tropical monsoon climate systems, via the westerly circulation. Finally, we also observe an increase in regional climate variability after the mid-Holocene, which we relate to changes in vegetation (forest) cover in the monsoon region through a land-surface albedo feedback.
Bibliographical noteFunding Information:
We thank J. Cao, A. Zhou, X. Liu and K. Zhang of Lanzhou University for field coring assistance; the Keck-CCAMS facility of University of California, Irvine for radiocarbon dating; the staff at LacCore (National Lacustrine Core Facility) of the University of Minnesota for initial core description and sub-sampling. The project was supported by the HK RGC ( HKU 703809P ) and HKU Stephen Hui Trust Fund ( 201103173003 ) to Z. Liu and Chinese NSF ( NSFC #40528001 ) and US NSF ( NSF EAR #0518774 ) to Z. Yu.
Copyright 2013 Elsevier B.V., All rights reserved.
- Arid Central Asia
- Climate variability