Meltwater and the global ocean conveyor: northern versus southern connections
Meltwater and the global ocean conveyor: northern versus southern connections
复制标题
DOI：
10.1016/s0921-8181(00)00087-4
复制
发表时间：
2001-10-01
影响因子：
3.9
通讯作者：
Haupt, BJ
中科院分区：
文献类型：
--
作者：
Seidov, D;Barron, E;Haupt, BJ
海洋环流对北大西洋表面通量变化的敏感性已成为解释气候变化的一个主要因素。南极底层水在调节这种变率中的作用受到的关注要少得多，限制了对十年到千年时间尺度气候变化的全面了解。新的分析表明，南部深水源可能会发生巨大变化（例如，在过去的800年里减少了三分之二）。这种变化可以大大改变上个千年的海洋环流模式。进一步的分析表明，在更新世的一些冰期旋回中，南半球导致了北方半球的变化，这意味着全球海洋输送带的跷跷板式振荡。南极洲海冰和冰盖融化的可能性与全球变暖有关，可能导致南部深水源的进一步减缓。这些结果要求对南大洋在推动全球海洋环流和气候变化方面的作用进行评估。针对海洋环流对北方和南半球高纬度地区表面盐度变化的反应进行的系统模型模拟表明，一个半球的融水影响可能导致另一个半球的源驱动的温盐输送带加强。这反过来又导致向极热传输的显著变化。此外，融水事件可导致深海变暖和深海水热膨胀，进而造成海平面大幅变化，即使没有大规模冰盖融化。(C)2001 Elsevier Science B.V.保留所有权利。
The sensitivity of the ocean circulation to changes in North Atlantic surface fluxes has become a major factor in explaining climate variability. The role of the Antarctic Bottom Water in modulating this variability has received much less attention, limiting the development of a complete understanding of decadal to millennial time-scale climate change. New analyses indicate that the southern deepwater source may change dramatically (e.g., experience a decrease of as much as two thirds during last 800 years). Such change can substantially alter the ocean circulation patterns of the last millennium. Additional analyses indicate that the Southern Hemisphere led the Northern Hemisphere changes in some of the glacial cycles of Pleistocene, implying a seesaw-type oscillation of the global ocean conveyor. The potential for melting of sea ice and ice sheets in the Antarctica associated with global warming can cause a further slowdown of the southern deepwater source. These results demand an assessment of the role of the Southern Ocean in driving changes of the global ocean circulation and climate. Systematic model simulation targeting the ocean circulation response to changes in surface salinity in the high latitudes of both Northern and Southern Hemispheres demonstrate that meltwater impacts in one hemisphere may lead to a strengthening of the thermohaline conveyor driven by the source in the opposite hemisphere. This, in turn, leads to significant changes in poleward heat transport. Further, meltwater events can lead to deep-sea warming and thermal expansion of abyssal water, that in turn cause a substantial sea-level change even without a major ice sheet melting. (C) 2001 Elsevier Science B.V. All rights reserved.