Dependence of abrupt Atlantic meridional ocean circulation changes on climate background states

作者：Gong Xun^*; Knorr Gregor; Lohmann Gerrit; Zhang Xu

来源：Geophysical Research Letters, 2013, 40(14): 3698-3704.

DOI：10.1002/grl.50701

• abrupt AMOC change
• South Labrador Sea
• last glacial-interglacial cycle

Abrupt decadal climate changes during the last glacial-interglacial cycle are less pronounced during maximum glacial conditions and absent during the Holocene. To further understand the underlying dynamics, we conduct hosing experiments for three climate states: preindustrial (PI), 32kiloannum before present (ka B.P.), and Last Glacial Maximum (LGM). Our simulations show that a stronger temperature inversion between the surface and intermediate layer in the South Labrador Sea induces a faster restart of convective processes (32ka B.P.>LGM>PI) during the initial resumption of the Atlantic meridional overturning circulation (AMOC). A few decades later, an AMOC overshoot is mainly linked to the advection of warmer and saltier intermediate-layer water from the tropical Atlantic into the South Labrador Sea, which causes a stronger deep-water formation than that before the freshwater perturbation. This mechanism is most pronounced during the 32ka B.P., weaker during the LGM and absent during the PI.

• 出版日期2013-7-28