第七届青年地学论坛

The abrupt climate event Younger Dryas (YD) has been extensively studied, however, its structure is still poorly understood. Climate in northeastern Brazil is very sensitive to the latitudinal position of the intertropical convergence zone (ITCZ) associated with abrupt climate change in the Atlantic. Here, we report changes in the ITCZ position within the YD by using precise speleothem multi-proxy records from northeastern Brazil. We provide evidence for a gradual northward migration of the ITCZ preceding poleward shifts of the westerlies and the polar front in northern high latitudes within the YD. This can be attributed to gradual increase in atmospheric CO₂ concentration as a consequence of the weakening Atlantic Meridional Overturning Circulation (AMOC). We suggest that a persistent increase in atmospheric CO₂ might have triggered a resumption of the AMOC and reorganization of the atmosphere circulation in the Atlantic during the mid-YD.
 

Speleothem; Younger Dryas; North Atlantic; Southern Hemisphere; AMOC; ITCZ