Connection of the Oxygen Isotope in Stalagmites from East Asia with the Large Scale Atmospheric-Oceanic Patterns

Abstract:

Cave stalagmites δ¹⁸O is associated with climate, but the specific climatic meaning of East Asian stalagmites δ¹⁸O remains unclear. Several recent researches suggest that East Asian stalagmites δ¹⁸O represents neither surface air temperature nor precipitation, but an integral variation of Asian monsoon circulation systems. It reflects a ratio of different water vapor sources. Since large-scale atmospheric-oceanic patterns such as Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO) show significant effects on the Asian monsoon circulation systems, in this work we explored the relationships between these atmospheric-oceanic patterns and the East Asian stalagmites δ¹⁸O during the last three centuries by using several reconstructed dataets together with instrumental records. Considering the human activities exert extraordinary impacts on climate, we compared the two separated periods, before and after the industrial revolution. The results show significant lead-lag connections between the East Asian stalagmites δ¹⁸O and the large-scale atmospheric-oceanic patterns. One positive correlation peaks when PDO leads the East Asian stalagmites δ¹⁸O by 3 years. This PDO-stalagmite connection is robust through the whole recent centuries. In comparison, the relations between AMO, NAO and the East Asian stalagmites δ¹⁸O exhibit significant differences in the post-industrial period and the pre-industrial period. Thus, the East Asian stalagmites δ¹⁸O may be a reflector of the signals of PDO.