Decoupled Asian monsoon intensity and precipitation during glacial-interglacial transitions on the Chinese Loess Plateau.

Zheng, Yukun; Liu, Hongyan; Yang, Huan; Wang, Hongya; Zhao, Wenjie; Zhang, Zeyu; Huang, Miao; Liu, Weihang · Nat Commun · 2022

basic_science · Level V

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Abstract

The discrepancies among the variations in global ice volume, cave stalagmite δ<sup>18</sup>O and rainfall reconstructed by cosmogenic <sup>10</sup>Be tremendously restrain our understanding of the evolution of the East Asian summer monsoon (EASM). Here, we present a 430-ka EASM mean annual precipitation record on the Chinese Loess Plateau obtained using branched glycerol dialkyl glycerol tetraethers based on a deep learning neural network; this rainfall record corresponds well with cave-derived δ<sup>18</sup>O data from southern China but differs from precipitation reconstructed by <sup>10</sup>Be. Both branched tetraether membrane lipids and cave δ<sup>18</sup>O may be affected by soil moisture and atmospheric temperature when glacial and interglacial conditions alternated and were thus decoupled from atmospheric precipitation; instead, they represent variations in the intensity of the EASM. Furthermore, we demonstrate that the brGDGT-DLNN method can significantly extend the temporal scale record of the EASM and is not restricted by geographic location compared with stalagmite records.

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