Zhang Zhaoru, Xie Chuan, Castagno Pasquale, England Matthew H, Wang Xiaoqiao, Dinniman Michael S, Silvano Alessandro, Wang Chuning, Zhou Lei, Li Xichen, Zhou Meng, Budillon Giorgio
Key Laboratory of Polar Ecosystem and Climate Change, Ministry of Education and School of Oceanography, Shanghai Jiao Tong University, Shanghai, China.
Shanghai Key Laboratory of Polar Life and Environment Sciences, Shanghai Jiao Tong University, Shanghai, China.
Nat Commun. 2024 Sep 18;15(1):8190. doi: 10.1038/s41467-024-52524-x.
Antarctic Bottom Water (AABW), which supplies the lower limb of the thermohaline circulation, originates from dense shelf water (DSW) forming in Antarctic polynyas. Here, combining a long mooring record of DSW measurements with numerical simulations and satellite data, we show that significant correlation exists between interannual variability of DSW production in the Ross Sea polynyas, where DSW contributes between 20-40% of the global AABW production, and the Southern Annular Mode (SAM). The correlation is largest when the Amundsen Sea Low (ASL) is weakened and shifted east of the Ross Sea. During positive SAM phases, enhanced offshore winds and lower air temperatures over the western Ross Sea increase sea ice production and promote DSW formation, with the opposite response during negative SAM phases. These processes ultimately modulate AABW thickness in the open ocean. A projected positive shift of the SAM and eastward displacement of the ASL thus has implications for the future of DSW and AABW formation.
南极底层水（AABW）为热盐环流的下层提供水源，它起源于南极冰间湖形成的高密度陆架水（DSW）。在此，我们将DSW测量的长期锚定记录与数值模拟及卫星数据相结合，表明罗斯海冰间湖的DSW产量年际变化与南半球环状模（SAM）之间存在显著相关性，罗斯海冰间湖的DSW产量占全球AABW产量的20%-40%。当阿蒙森海低压（ASL）减弱并向东移至罗斯海以东时，这种相关性最为显著。在SAM正相位期间，罗斯海西部增强的离岸风及较低的气温增加了海冰产量并促进了DSW的形成，而在SAM负相位期间则出现相反的响应。这些过程最终调节了公海中AABW的厚度。因此，预计SAM的正向变化及ASL的东移对DSW和AABW形成的未来具有重要影响。
