Researchers from the Institute of Earth Environment, Chinese Academy of Sciences, including Dr. Hong Ao, Dr. Yougui Song, Senior Engineer Xiaoke Qiang, and Associate Researcher Peng Zhang, along with international experts, conducted an in-depth study on the changes in the track and millennial-scale variations of the Asian winter monsoon before and after the expansion of the ice sheets in the Northern Hemisphere using the Chongxin red clay/loess profile on the Loess Plateau. They found that 2.7 million years ago, the expansion of the Northern Hemisphere ice sheets led to the enhancement of the track and millennial-scale variations of the Asian winter monsoon. This research was recently published in Nature Communications.
By utilizing magnetostratigraphy, the team revealed that the Chongxin profile recorded continuous geomagnetic polarity features from the Gilbert-Gauss boundary to the early Matuyama negative polarity. Based on magnetostratigraphic dating, they reconstructed the evolutionary history of the winter monsoon from the late Pliocene to the early Pleistocene using sediment grain size as a physical parameter. The results showed that while the significant expansion of the Northern Hemisphere ice sheets increased the intensity of the winter monsoon, it did not alter the periodic evolution of the winter monsoon track scale, which consistently maintained two synchronous evolution periods of approximately 40,000 years and ~100,000 years, similar to global sea level changes. Before and after the formation of the Arctic ice sheets, the winter monsoon has always exhibited significant millennial-scale fluctuations superimposed on track scale changes, primarily controlled by astronomical forcing and internal climate dynamics of the Earth.
For more information, refer to the related paper: https://doi.org/10.1038/s41467-024-47274-9
