The Southern Hemisphere Westerly Winds Belt (SWW)affects the exchange of carbon dioxide between the southern ocean and atmosphere by changing the ventilation of the southern ocean during last Deglaciation.During this period,the ventilation of deep southern ocean usually accompanied with the vari-ation of atmosphere and ocean circulation.As an example,changes in the location and intensity of SWW and the Atlantic Meridional Overturning Circulation (AMOC ) changes in intensity.Some studies suggested that the belt of the SWW may move southward towards the polar at the beginning of deglacia-tion,and this shift of SWW could exert a strong control on Southern Ocean upwelling.While other studies suggested that compared to other factors,the changes in AMOC have a more important control on South-ern Ocean stratification,and this could exert a stronger control on Southern Ocean upwelling.This could be explained by the mechanism that decreased formation of North Atlantic Deep Water (NADW)could lead to a weaker AMOC strength,which results in a northward mixed boundary of Antarctic Bottom Water (AABW)and NADW.Therefore,a weaker stratification and increasing upwelling of deep Southern Ocean existed during the Last Deglaciation.Both of these mechanisms could lead to the variations of venti-lation or stratification in the Southern Ocean,which strongly coincided with the variation of atmospheric carbon dioxide concentration.Thus,discussions of the mechanisms which carbon dioxide was released by upwelling from the deep southern ocean during the most recent transition from glacial to interglacial condi-tions,have concentrated on the mechanisms about the variation of the Southern ocean ventilation.This passage following deciphers about two scenarios' mechanisms of the most important driving force of the Southern ocean ventilation in the following graphs.In addition to these two driven forces,some new stud-ies have found that the northward expansion and poleward retreat of Ross Sea Bottom Water could exert a strong control on the Southern Ocean stratification.However,there are many mechanisms for deep South-ern Ocean circulation.For example,variations of SWW strength and position,changes of AMOC strength and expansion/retreat of Ross Sea Bottom Water,are other mechanisms of the variation of Southern Ocean circulation.These mechanisms change the Southern Ocean circulation in different ways.Meanwhile,these processes could respond positively to the variations of the atmospheric p CO2 in certain extent.%末次冰消期时,南大洋深层水流通性增强和大气CO 2分压(大气p CO2)升高存在密切联系.该时期南大洋深部流通性增强的同时会伴随着大气与大洋环流模式的一系列变化,例如南半球西风带(Southern Hemisphere Westerly Winds Belt,SWW)位置和强度以及大西洋经向翻转流(Atlantic Meridional Overturning Circulation,AMOC)强度的变化.一些关于控制南大洋流通性变化机制方面的研究发现,SWW的经向摆动可对南大洋深部流通性产生强烈影响.末次冰消期时SWW南移,会强化南大洋风驱上升流,增强南大洋的通风.另一些研究认为AMOC变化对南大洋深部流通性具有更为强烈的影响,末次冰消期时北大西洋深层水(North Atlantic Deep Water,NADW)生成减弱导致AMOC强度减弱,这一过程使得NADW与绕极深层水(Circumpolar Deep Water,CDW)的混合边界北移,从而减弱南大洋水体成层化,增强了南大洋深层水上涌.上述2种模式均可能引起南大洋深部流通状况的改变,并最终导致冰消期大气p CO2上升.除SWW与AMOC驱动南大洋深部流通状况的改变之外,最新研究发现南大洋罗斯海似乎可以通过其自身底层水的北向扩张与极向退却进一步影响南大洋深部流通状况.总的来说,控制南大洋深部流通状况的并非单一机制,SWW与AMOC以及罗斯海底层水等诸多因素在控制南大洋流通状况变化的同时也会以不同的方式在一定程度上积极的响应大气p CO2的变化.
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