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.