Accelerated freshening of Antarctic Bottom Water over the last decade in the Southern Indian Ocean.
Accelerated freshening of Antarctic Bottom Water over the last decade in the Southern Indian Ocean.
复制标题
在印度洋南部，在过去的十年中，南极底水的新鲜加速。
DOI：
10.1126/sciadv.1601426
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发表时间：
2017-01
期刊：
影响因子：
13.6
通讯作者：
Schatzman C
中科院分区：
文献类型：
--
作者：
Menezes VV;Macdonald AM;Schatzman C
2007年至2016年，澳大利亚-南极盆地的加速淡水化减少了南极底层水的变暖。南大洋深海沃茨在南极洲周围的形成地点与大气层接触，不仅在它们环绕地球仪移动时带来气候变化的信号，而且还通过吸收热量和海平面上升促成了这种变化。在南大洋的印度部分的一条重复的水文线，在过去的二十年中被占据了三次（1994年，2007年，以及最近的2016年），揭示了南极底层水（AABW）继续变得更加新鲜（0.004 ± 0.001 kg/g decade−1），温度较高（0.06° ± 0.01°C decade−1），密度较低（0.011 ± 0.002 kg/m3 decade−1）。澳大利亚-南极海盆的最新观测结果显示，2007年至2016年期间，AABW的清新速度（0.008 ± 0.001 kg/g decade−1）比1994年至2007年期间的0.002 ± 0.001 kg/g decade−1显著加快。刷新是，在一定程度上，负责的平均温度-盐度曲线向低密度的整体移动。显著的淡水化可能与2010年发生在乔治五世/阿德利陆地海岸的一次突然的冰山-冰川碰撞和冰解事件有关，该海岸是澳大利亚-南极海盆底层沃茨的主要来源地区。由于AABW是全球翻转环流的一个关键组成部分，底层水密度的持续下降和空间高度的相关增加，导致持续变暖和清新，具有重要的后果超出南印度洋。
Accelerated freshening reduced warming of Antarctic Bottom Water from 2007 to 2016 in the Australian-Antarctic Basin. Southern Ocean abyssal waters, in contact with the atmosphere at their formation sites around Antarctica, not only bring signals of a changing climate with them as they move around the globe but also contribute to that change through heat uptake and sea level rise. A repeat hydrographic line in the Indian sector of the Southern Ocean, occupied three times in the last two decades (1994, 2007, and, most recently, 2016), reveals that Antarctic Bottom Water (AABW) continues to become fresher (0.004 ± 0.001 kg/g decade−1), warmer (0.06° ± 0.01°C decade−1), and less dense (0.011 ± 0.002 kg/m3 decade−1). The most recent observations in the Australian-Antarctic Basin show a particularly striking acceleration in AABW freshening between 2007 and 2016 (0.008 ± 0.001 kg/g decade−1) compared to the 0.002 ± 0.001 kg/g decade−1 seen between 1994 and 2007. Freshening is, in part, responsible for an overall shift of the mean temperature-salinity curve toward lower densities. The marked freshening may be linked to an abrupt iceberg-glacier collision and calving event that occurred in 2010 on the George V/Adélie Land Coast, the main source region of bottom waters for the Australian-Antarctic Basin. Because AABW is a key component of the global overturning circulation, the persistent decrease in bottom water density and the associated increase in steric height that result from continued warming and freshening have important consequences beyond the Southern Indian Ocean.