Obliquity Induced Latitudinal Migration of the Intertropical Convergence Zone During the Past ∼410 kyr

Abstract

Obliquity influences the latitudinal position of the Intertropical Convergence Zone (ITCZ). However, the specific forcing mechanism remains unclear due to scarcity of long-term and high-resolution precipitation records from the Indo-Pacific region. Here, we present a new, extended, high-resolution (∼2 kyr) precipitation record covering the past ∼410 kyr from a marine sedimentary sequence collected at the southern margin of the ITCZ's latitudinal displacement within the Indo-Pacific region. By integrating this new precipitation record with the published precipitation records at the northern margin of the ITCZ's latitudinal displacement, we found that precipitation in the Northern and Southern Hemispheres varied in anti-phase on the obliquity band, indicating that the latitudinal migration of the ITCZ was dominated by obliquity. The obliquity forcing on the latitudinal migrations of the ITCZ could be imparted by variations in the North Atlantic sea ice cover, resulting from Agulhas leakage induced changes in the ventilation strength of the Atlantic meridional overturning circulation.