Pacific Walker Circulation modulated millennial-scale East Asian summer monsoon rainfall variability over the past 40 kyr

Abstract

The millennial-scale hydroclimate variability in East Asia has been debated for a long time due to the lack of reliable precipitation records from southern China and inconsistent model simulations. Here, we reconstruct a 40-kyr rainfall record for southern China and Taiwan based on enviro-magnetic and clay mineral proxy parameters from a northern South China Sea marine sediment core. Both proxies suggest reduced East Asian Summer Monsoon (EASM) precipitation in the southern China-Taiwan region during North Atlantic cooling episodes. After integration with other EASM precipitation records and modeling results, we conclude that the spatial precipitation pattern across Southeast Asia is closely related to the strength of the Pacific Walker Circulation. This interpretation is supported by a model simulation that emphasizes the role of the Walker Circulation in transferring North Atlantic climate variability to the East Asian hydroclimate. Our findings contribute to resolving the disparities between precipitation proxies and model simulations in Southeast Asia.