A 550,000-year record of East Asian monsoon rainfall from Be in loess.

Cosmogenic Be flux from the atmosphere is a proxy for rainfall. Using this proxy, we derived a 550,000-year-long record of East Asian summer monsoon (EASM) rainfall from Chinese loess. This record is forced at orbital precession frequencies, with higher rainfall observed during Northern Hemisphere summer insolation maxima, although this response is damped during cold interstadials. The Be monsoon rainfall proxy is also highly correlated with global ice-volume variations, which differs from Chinese cave δO, which is only weakly correlated. We argue that both EASM intensity and Chinese cave δO are not governed by high-northern-latitude insolation, as suggested by others, but rather by low-latitude interhemispheric insolation gradients, which may also strongly influence global ice volume via monsoon dynamics.