Evolution of Near‐Surface Wind Strength in Northeastern Arid Central Asia During the Holocene
Fuyuan Gao, Xiangmin Zheng, Jia Jia, Kaiming Li, Dunsheng Xia, Junhuai Yang, Hao Lu, Fuxi Shi, Zixuan Chen, Shuyuan Wang
Abstract
Abstract Wind dynamics in dust source areas are influenced by climate change on both regional and global scales. Northeastern arid central Asia is one of the most important sources of Asian dust. We conducted grain size analyses of the extracted quartz component of bulk samples from four Holocene aeolian sedimentary sequences in northeastern arid central Asia, in order to reconstruct variations in strength of near‐surface wind, and discussed the possible mechanism. X‐ray diffraction and geochemical analyses were also conducted. The results suggest that in the study area the mean grain size of the quartz component of aeolian sediments is a more reliable proxy for the strength of near‐surface wind and Siberian high‐pressure system. Stronger near‐surface wind and Siberian high‐pressure system occurred during the early to middle Holocene and subsequently their gradually weakened. Lower winter insolation, lower atmospheric CO 2 content, and remnant high‐latitude continental ice‐sheets resulted in relatively low winter temperatures in middle and high latitudes of the Northern Hemisphere during the early to middle Holocene. The lower winter temperatures indicate a stronger Siberian high‐pressure system, which may have been the cause of the stronger near‐surface winds. Due to increasing winter solar insolation and atmospheric CO 2 content, and the shrinking high‐latitude continental ice‐sheets, the Siberian high‐pressure system weakened in response to rising winter temperatures during the middle to late Holocene, likely resulting in decreased near‐surface wind strength.