GEOGRAPHY

New progress has been made in the study of the 150,000-year westerly-monsoon synergy


Understanding the evolution and interaction of the mid-latitude westerly and East Asian monsoons is critical to understanding Asia’s climate dynamics. At present, most of the research on the westerly region has focused on the Holocene since the Holocene, and the climate characteristics of the Holocene are significantly different from the monsoon region. In contrast, the lack of long-scale records in the westerly region also leads to the unclear interaction between westerly and monsoon winds from glacial-interglacial to millennial scales.

In response to the above problems, the Loess and Climate Change Team of the Institute of Earth Environment, Chinese Academy of Sciences, together with Professor Jef Vandenberghe of Vrije Universiteit Amsterdam, an internationally renowned sedimentologist and others, reconstructed the evolution history of westerly-monsoon over the past 150,000 years through particle size and organic matter indicators based on two high sedimentary rate loess drill holes in the Ili Basin and the Linxia Basin of the Loess Plateau in Xinjiang.

Comparison of particle size, organic matter and magnetic susceptibility in Linxia and Zhaosu drilled holes over 150,000 years. (Photo courtesy of the paper team)

The results show that the East Asian winter wind and the west wind show synchronous changes in the glacial-interglacial period and precession scale. The humidity variation in the two regions is consistent in the glacial-interglacial scale, and there is a certain dislocation phase in the precession scale. The cross-spectrum results showed that the humidity variation in the westerly region lagged behind the East Asian monsoon region by about 2,000 years during the MIS5 period. On the millennial scale, wind and humidity changes in the westerly and East Asian monsoon regions are closely related to cold events in the North Atlantic. Based on the TraCE-21 ka simulation results, ice sheet, insolation and high-latitude freshwater injection jointly affect climate change in the westerly and monsoon regions during glacial-interglacial periods, precession and millennium scales, respectively.

The study, which explores the evolution history of westerly-monsoon from the three scales of glacial-interglacial period, precession and millennium, was recently published online in the internationally renowned journal Quaternary Science Reviews, and the second comprehensive scientific expedition to the Tibetan Plateau was the first funding. (Source: Yan Tao, China Science News)

Related paper information:https://doi.org/10.1016/j.quascirev.2023.108281



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