Abstract

A two-stage recovery of Atlantic meridional overturning circulation (AMOC) during Bølling Allerød (BA) is revealed in the first transient simulation of last deglaciation in a fully coupled general circulation model (Transient Simulation of Climate Evolution over the Last 21,000 Years (TraCE-21000... Show moreA two-stage recovery of Atlantic meridional overturning circulation (AMOC) during Bølling Allerød (BA) is revealed in the first transient simulation of last deglaciation in a fully coupled general circulation model (Transient Simulation of Climate Evolution over the Last 21,000 Years (TraCE-21000)). After being suppressed during the Heinrich 1 event, North Atlantic Deep Water (NADW) formation first reinitiates in the Labrador Sea in stage 1 and then reinitiates in the Greenland-Iceland-Norwegian (GIN) seas in stage 2. This feature is derived from the investigation of NADW formation in its two origins with a newly developed method and is confirmed by the comprehensive analysis of relative variables. A new mechanism is proposed to interpret the northward asynchronous reinitiation of NADW during BA. In addition, our work also points out that the generation of the AMOC overshoot is associated with the reinitiation of NADW in GIN seas. Show less