Climate significance of speleothem δ18O from central China on decadal timescale

Speleothem-based oxygen isotopic sequences have been widely used to reveal regional climatic changes worldwide. However, the climatic significance of speleothem δ18O variations in monsoonal China on decadal- to annual timescales remains in debate, which limits its application to paleoclimate reconstruction in the world's largest country by population. In this study, we analyzed a seasonally resolved δ18O record of an annually layered stalagmite, XL21 whose variability covers a period of 98 years (1912-2009 AD), from Xianglong Cave, central China. The annual δ18O trend shows an inverse relationship with local monsoon precipitation, suggesting speleothem δ18O variations in this area can reflect monsoon precipitation at least on decadal timescale. Changes in moisture sources and transport pathways have little effect on the δ18O variations in speleothems/monsoon precipitation on decadal timescale, which may be ascribed to similar distances from this region to the two main moisture sources, the Bay of Bengal and West Pacific. There is an anti-phase relationship between speleothem δ18O records from central China and India during the last 98 years, which indicates the relationship between Indian monsoon intensity and speleothem δ18O from central China on short timescales requires further investigation.