Late Holocene monsoon precipitation changes in southern China and their linkage to Northern Hemisphere temperature

Here we present a reconstruction of a ~5 year-resolution summer monsoon rainfall record for the past 3200 years, based on 622 pairs of δ18O and δ13C and 29 230Th dates from a stalagmite (Wu37) from Wulu Cave in southern China. The monsoon precipitation variations indicated by our record and other cave records nearby were inversely related to changes in Northern Hemisphere temperature over the past two millennia, in particular to variations in the thermal gradient between the Northern and Southern hemispheres. In addition, we find that variations of monsoon rainfall in southern China on multi-centennial to centennial timescales are inversely correlated with observed rainfall in the core monsoon region of India and in the northern fringe of the Asian summer monsoon region in China. This spatial pattern of rainfall variability can be interpreted as a result of the migration of the intertropical convergence zone that is likely dominated by the interhemispheric thermal gradient via cross-equatorial airflows.

本研究呈现了基于我国南方武隆洞内碳酸盐岩（Wu37）的622组δ18O和δ13C同位素比值及29组230Th年代数据，重建了过去3200年以来的夏季季风降雨记录，其时间分辨率为约5年。所记录的季风降水变化与邻近洞穴记录相一致，显示与过去两千年北半球温度变化呈负相关，特别是与南北半球热梯度的变化密切相关。此外，我们发现，中国南方多世纪至世纪时间尺度上的季风降雨变化与印度季风核心区域及中国亚洲夏季风北部边缘的观测降雨呈负相关性。这种降雨变率的空间模式可被解释为热带辐合带迁移的结果，该迁移可能主要由跨赤道气流所驱动的半球间热梯度所主导。