Abstract: The stalagmite δ¹⁸O_c records from southern China serve as a crucial paleoclimate archive for reconstructing orbitaland millennial-scale variations of the Asian monsoon system. Nevertheless, the precise linkage between these δ¹⁸O_c signals and regional precipitation remains debated, posing challenges for both the climatic interpretation of δ¹⁸O_c variations and investigations of driving mechanisms of monsoon variations. This study synthesizes published stalagmite δ¹⁸O_c records (21-11 ka B.P.) from southern China with HadCM3B model simulations to examine the δ¹⁸O_c -precipitation relationship during the last deglaciation. Our analysis reveals distinct scale-dependent relationships: on orbital timescales, the δ¹⁸O_c variations reliably track long-term changes in summer precipitation, while millennial-scale δ¹⁸O_c fluctuations primarily reflect variations in annual precipitation. The transition from glacial to interglacial conditions is marked by progressively depleted δ¹⁸O_c values, corresponding to increasing summer rainfall. In contrast, during abrupt climate events such as YD and HS-1, enriched δ¹⁸O_c values coincide with enhanced annual precipitation. Through comparative analysis of δ¹⁸O_p anomalies with the precipitation-weight and stalagmite δ¹⁸O_c anomalies, we demonstrate that while the aforementioned relationships exist across different timescales, stalagmite δ¹⁸O_c cannot be unambiguously interpreted as a direct proxy for either summer or annual precipitation amounts. 

Key words: Southern China, stalagmite δ¹⁸O_c, climate model, precipitation δ¹⁸O_p