Nordic Seas Hydrography in the Context of Arctic and North Atlantic Ocean Dynamics
Nordic Seas Hydrography in the Context of Arctic and North Atlantic Ocean Dynamics
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DOI：
10.1175/jpo-d-20-0071.1
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发表时间：
2020-11
影响因子：
3.5
通讯作者：
J. Kenigson;M. Timmermans
中科院分区：
文献类型：
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作者：
J. Kenigson;M. Timmermans
深对流混合的一个关键网站，北欧海洋的水文，是由各种过程控制。一方面，北冰洋的出口被认为使北大西洋和北欧海域焕然一新，就像20世纪70年代至90年代的大盐度异常（GSA）一样。另一方面，北欧海的盐度与穿过格陵兰-苏格兰海脊的大西洋流入量的盐度相互关联，使北冰洋出口的作用不确定。在这项研究中，北欧海洋水文学，北大西洋的亚北极锋（SAF）[将相对凉爽，新鲜的副极地环流（SPG）的水团与温暖，含盐的副热带环流（STG）分开]和大气强迫的数十年时间序列（1950-2018）进行了检查，并提出了统一的观点。北欧海淡水含量的协变十年的时间尺度与SAF的位置。当SPG较强时，SAF的平均位置向东移动，增加了副极地相对于副热带水源对大西洋流入的贡献，反之亦然。这表明北冰洋通量主要通过间接方式影响北欧海洋的水文学（即，通过刷新SPG）。两年的案例研究与异常NAO条件说明北大西洋动力学如何与SAF的位置（如水文特性和上层水柱的分层变化所示），因此，大西洋流入和北欧海洋的属性。
The hydrography of the Nordic seas, a critical site for deep convective mixing, is controlled by various processes. On one hand, Arctic Ocean exports are thought to freshen the North Atlantic Ocean and the Nordic seas, as in the Great Salinity Anomalies (GSAs) of the 1970s–1990s. On the other hand, the salinity of the Nordic seas covaries with that of the Atlantic inflow across the Greenland–Scotland Ridge, leaving an uncertain role for Arctic Ocean exports. In this study, multidecadal time series (1950–2018) of the Nordic seas hydrography, Subarctic Front (SAF) in the North Atlantic Ocean [separating the water masses of the relatively cool, fresh Subpolar Gyre (SPG) from the warm, saline Subtropical Gyre (STG)], and atmospheric forcing are examined and suggest a unified view. The Nordic seas freshwater content is shown to covary on decadal time scales with the position of the SAF. When the SPG is strong, the SAF shifts eastward of its mean position, increasing the contribution of subpolar relative to subtropical source water to the Atlantic inflow, and vice versa. This suggests that Arctic Ocean fluxes primarily influence the hydrography of the Nordic seas via indirect means (i.e., by freshening the SPG). Case studies of two years with anomalous NAO conditions illustrate how North Atlantic Ocean dynamics relate to the position of the SAF (as indicated by hydrographic properties and stratification changes in the upper water column), and therefore to the properties of the Atlantic inflow and Nordic seas.