Rebound of shelf water salinity in the Ross Sea
Rebound of shelf water salinity in the Ross Sea
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DOI：
10.1038/s41467-019-13083-8
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发表时间：
2019-11-29
影响因子：
16.6
通讯作者：
Budillon, Giorgio
中科院分区：
文献类型：
--
作者：
Castagno, Pasquale;Capozzi, Vincenzo;Budillon, Giorgio
南极底层水（AABW）提供全球翻转环流的下肢，并为深海提供通风。近几十年来，AABW已经变暖，清新，体积减少。罗斯海底水（RSBW），AABW的第二大来源，经历了最大的淡化。在这里，我们使用23年的夏季测量记录的罗斯海高盐度陆架水（HSSW），RSBW的前兆盐度的时间变化。HSSW盐度在1995年至2014年期间下降，与1958年至2008年期间观察到的淡水化一致。然而，HSSW盐度在2014年后急剧反弹，2018年的数值与20世纪90年代中后期观察到的数值相似。在大陆架上的五个地点观测到的近同步的盐度年际波动表明，上游预处理和大尺度强迫影响HSSW盐度。最近盐度增加的速度、幅度和持续时间在（稀疏的）观测记录中是不寻常的。
Antarctic Bottom Water (AABW) supplies the lower limb of the global overturning circulation and ventilates the abyssal ocean. In recent decades, AABW has warmed, freshened and reduced in volume. Ross Sea Bottom Water (RSBW), the second largest source of AABW, has experienced the largest freshening. Here we use 23 years of summer measurements to document temporal variability in the salinity of the Ross Sea High Salinity Shelf Water (HSSW), a precursor to RSBW. HSSW salinity decreased between 1995 and 2014, consistent with freshening observed between 1958 and 2008. However, HSSW salinity rebounded sharply after 2014, with values in 2018 similar to those observed in the mid-late 1990s. Near-synchronous interannual fluctuations in salinity observed at five locations on the continental shelf suggest that upstream preconditioning and large-scale forcing influence HSSW salinity. The rate, magnitude and duration of the recent salinity increase are unusual in the context of the (sparse) observational record.