Mega-Tripolar Precipitation Change Accompanying Water Isotopes in Holocene Asian Summer Monsoon Reanalysis

The climatic interpretations of speleothem δ¹⁸O_c records over Asian summer monsoon (ASM) region have been controversial. Here, combining speleothem δ¹⁸O_c records with the first transient Holocene simulation of an isotope-enabled earth system model, we reconstruct a dynamically consistent spatio-temporal evolution of the ASM precipitation using paleoclimate data assimilation. Our reconstruction finds a new mega-tripolar pattern of precipitation variations accompanying a continental-wide enrichment of δ¹⁸O_c from the early to late Holocene over the entire ASM continental region. Precipitation peaked in the early Holocene over South Asia, northern China and southern China, but in the late Holocene over central China. This mega-tripolar pattern of precipitation variations can help resolve the long-standing controversy about the timing of Holocene ASM precipitation peaks reconstructed from various proxy records.