Stabilization of dense Antarctic water supply to the Atlantic Ocean overturning circulation
Stabilization of dense Antarctic water supply to the Atlantic Ocean overturning circulation
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DOI：
10.1038/s41558-019-0561-2
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发表时间：
2019-10-01
影响因子：
30.7
通讯作者：
Meredith, Michael P.
中科院分区：
文献类型：
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作者：
Abrahamsen, E. Povl;Meijers, Andrew J. S.;Meredith, Michael P.
大西洋翻转环流的下肢由密集的南极底层水（AABW）下沉补充，该底层水通过南极洲附近强烈的空气-海冰相互作用形成，特别是在威德尔海（1）。在过去的三十年里，大西洋和其他地方的AABW已经变暖，清新和体积下降（2-7），这表明海洋翻转正在进行重大重组（8，9）。然而，未来AABW对大西洋翻转环流的贡献尚不清楚。在这里，使用AABW在斯科舍海，最直接的途径从威德尔海到大西洋的观测，我们显示了最近停止的AABW供应大西洋翻转环流的下降。从20世纪90年代初到2014年，在AABW通流中观察到的致密层体积下降最严重;此后，它已经稳定并部分恢复。我们将这些变化与上游深海沃茨的沉积物类别的变化联系起来。我们的研究结果表明，以前观察到的大西洋深渊稠密水供应的下降可能正在稳定或逆转，因此需要重新评估南极对翻转环流，海平面，行星尺度热量分布和全球气候的影响（2，3，8）。
The lower limb of the Atlantic overturning circulation is resupplied by the sinking of dense Antarctic Bottom Water (AABW) that forms via intense air-sea-ice interactions next to Antarctica, especially in the Weddell Sea(1). In the last three decades, AABW has warmed, freshened and declined in volume across the Atlantic Ocean and elsewhere(2-7), suggesting an ongoing major reorganization of oceanic overturning(8,9). However, the future contributions of AABW to the Atlantic overturning circulation are unclear. Here, using observations of AABW in the Scotia Sea, the most direct pathway from the Weddell Sea to the Atlantic Ocean, we show a recent cessation in the decline of the AABW supply to the Atlantic overturning circulation. The strongest decline was observed in the volume of the densest layers in the AABW throughflow from the early 1990s to 2014; since then, it has stabilized and partially recovered. We link these changes to variability in the densest classes of abyssal waters upstream. Our findings indicate that the previously observed decline in the supply of dense water to the Atlantic Ocean abyss may be stabilizing or reversing and thus call for a reassessment of Antarctic influences on overturning circulation, sea level, planetary-scale heat distribution and global climate(2,3,8).