当前位置: X-MOL 学术Nat. Geosci. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Recent recovery of Antarctic Bottom Water formation in the Ross Sea driven by climate anomalies
Nature Geoscience ( IF 18.3 ) Pub Date : 2020-11-16 , DOI: 10.1038/s41561-020-00655-3
Alessandro Silvano , Annie Foppert , Stephen R. Rintoul , Paul R. Holland , Takeshi Tamura , Noriaki Kimura , Pasquale Castagno , Pierpaolo Falco , Giorgio Budillon , F. Alexander Haumann , Alberto C. Naveira Garabato , Alison M. Macdonald

Antarctic Bottom Water (AABW) supplies the lower limb of the global overturning circulation, ventilates the abyssal ocean and sequesters heat and carbon on multidecadal to millennial timescales. AABW originates on the Antarctic continental shelf, where strong winter cooling and brine released during sea ice formation produce Dense Shelf Water, which sinks to the deep ocean. The salinity, density and volume of AABW have decreased over the last 50 years, with the most marked changes observed in the Ross Sea. These changes have been attributed to increased melting of the Antarctic Ice Sheet. Here we use in situ observations to document a recovery in the salinity, density and thickness (that is, depth range) of AABW formed in the Ross Sea, with properties in 2018–2019 similar to those observed in the 1990s. The recovery was caused by increased sea ice formation on the continental shelf. Increased sea ice formation was triggered by anomalous wind forcing associated with the unusual combination of positive Southern Annular Mode and extreme El Niño conditions between 2015 and 2018. Our study highlights the sensitivity of AABW formation to remote forcing and shows that climate anomalies can drive episodic increases in local sea ice formation that counter the tendency for increased ice-sheet melt to reduce AABW formation.



中文翻译:

气候异常导致罗斯海南极底水形成的最新恢复

南极底水(AABW)为全球翻转循环的下肢提供能量,为深海通风,并在数十年到千年的时间尺度上隔离了热量和碳。AABW起源于南极大陆架,在那里强大的冬季降温和海冰形成过程中释放的盐水产生了密集的积水,该积水沉入深海。在过去的50年中,AABW的盐度,密度和体积均有所下降,其中罗斯海的变化最为明显。这些变化归因于南极冰盖融化的增加。在这里,我们使用原位观测来记录在罗斯海形成的AABW的盐度,密度和厚度(即深度范围)的恢复,其2018-2019年的性质与1990年代观察到的相似。恢复是由于大陆架上海冰形成增加所致。在2015年至2018年期间,异常的正南环空模式和极端的厄尔尼诺现象相伴而来的异常强风触发了海冰形成的增加。我们的研究强调了AABW形成对远程强迫的敏感性,并表明气候异常可以推动爆发性增加在局部海冰形成中,这抵消了冰盖融化增加以减少AABW形成的趋势。

更新日期:2020-11-16
down
wechat
bug