Dole effect as a measurement of the low-latitude hydrological cycle over the past 800 ka.

Abstract

The quest of geological proxies to evaluate low-latitude hydrological changes at a planetary scale remains an ongoing issue. The Dole effect is such a potential proxy owing to its global character. We propose a new approach to recalculate the fluctuation of the Dole effect (∆DE*) over the past 800 thousand years (ka). The ∆DE* calculated this way is dominated by precession cycles alone, with lesser variance in the obliquity bands and almost no variance in the eccentricity bands. Moreover, the ∆DE* is notably correlated with Chinese stalagmite δ¹⁸O record over the past 640 ka; simulated terrestrial rainfall changes between 30°N and 30°S over the past 300 ka. Our findings highlight the predominant role of the low-latitude hydroclimate in governing the ∆DE* on orbital time scales, while high-latitude climate impacts are negligible. In turn, we argue that the ∆DE* can be used to indicate low-latitude hydrological changes at a global extent.