气候变化领域集成服务门户

As an important component of the global monsoon system, the intensity of East Asian summer monsoon (EASM) influences lives and economic development of more than 2 billion people. The last interglacial period, also known as Marine Isotope Stage 5 (MIS 5), has been thoroughly investigated due to its similarity to the modern interglacial period (MIS 1). According to records from Chinese stalagmites and loess deposits, evolving history of EASM intensity during MIS5 can be divided into 5 sub-stages, i.e., 5a-5e. However, during the 3 warm sub-stages (5a, 5c, and 5e), evolving history of EASM intensity recorded by Chinese stalagmites and loess deposits is apparently different. Oxygen isotope (delta O-18) records of stalagmites demonstrate that the EASM intensity during MIS5e, 5c, and 5a is not obviously different. On the other hand, EASM intensity apparently decreased from MIS5e to 5c and 5a based on Chinese loess deposits records. The discrepancy between Chinese stalagmite and loess deposits reveals that delta O-18 records of stalagmites may not be a pure indicator of EASM intensity. The relationship between delta O-18 and EASM intensity is not linear. Based on delta O-18 data of modern precipitation from 21 weather stations within major monsoon area in China (MMAC, ca. 110A degrees E to 122A degrees E, 18A degrees N to 41A degrees N), we speculate that Chinese stalagmite delta O-18 values recorded changes of delta O-18 of summer precipitation as well as adjustment from delta O-18 of winter precipitation. Inconsistent records from Chinese stalagmites and loess deposits indicate that further investigations are needed to study the mechanism and fractionation of delta O-18 in stalagmites collected in China.