Depth of origin of ocean-circulation-induced magnetic signals
Depth of origin of ocean-circulation-induced magnetic signals
复制标题
海洋环流引起的磁信号的起源深度
DOI：
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Maik Thomas
中科院分区：
文献类型：
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作者：
C. Irrgang;J. Saynisch‐Wagner;Maik Thomas
抽象的。当世界海洋穿过周围的地磁核时
电场，电流在整个海洋盆地产生。这些
海洋电流感应微弱的磁信号，
在海洋之外可以观察到，并允许推断大规模的
水、热和盐度的海洋输送。海洋磁场
场是一个积分量，对于一阶，它正比于
深度积分和电导率加权洋流。但
不同深度的海洋输运对海洋的具体贡献
运动诱导过程仍不清楚，并在本研究中进行了检查。我们
显示了由于海洋环流引起大尺度运动感应
主要由海洋上层2000米的洋流产生
盆地特别是，我们的研究结果允许将区域模式与
海洋磁场对相应海洋输运的影响
深度相比之下，3000米以下的洋流只贡献了一小部分。
海洋感应磁信号强度的分数，其值高达
0.2 nT，在Swarm卫星高度小于0.1 nT。
因此，海洋环流引起的潜在卫星观测
发现磁信号可能对深海洋流不敏感。
此外，它表明，海洋引起的年时间变化，
南极绕极流区域的磁场包含
关于1000米以下次表层洋流的资料，
时期具体来说，具有次月周期的洋流主导着
海洋感应磁场的年度时间变化。 电磁学（数值方法）-地磁学和古地磁学（地磁感应）-地球物理学史（输运）
Abstract. As the world ocean moves through the ambient geomagnetic core
field, electric currents are generated in the entire ocean basin. These
oceanic electric currents induce weak magnetic signals that are principally
observable outside of the ocean and allow inferences about large-scale
oceanic transports of water, heat, and salinity. The ocean-induced magnetic
field is an integral quantity and, to first order, it is proportional to
depth-integrated and conductivity-weighted ocean currents. However, the
specific contribution of oceanic transports at different depths to the
motional induction process remains unclear and is examined in this study. We
show that large-scale motional induction due to the general ocean circulation
is dominantly generated by ocean currents in the upper 2000 m of the ocean
basin. In particular, our findings allow relating regional patterns of the
oceanic magnetic field to corresponding oceanic transports at different
depths. Ocean currents below 3000 m, in contrast, only contribute a small
fraction to the ocean-induced magnetic signal strength with values up to
0.2 nT at sea surface and less than 0.1 nT at the Swarm satellite altitude.
Thereby, potential satellite observations of ocean-circulation-induced
magnetic signals are found to be likely insensitive to deep ocean currents.
Furthermore, it is shown that annual temporal variations of the ocean-induced
magnetic field in the region of the Antarctic Circumpolar Current contain
information about sub-surface ocean currents below 1000 m with intra-annual
periods. Specifically, ocean currents with sub-monthly periods dominate the
annual temporal variability of the ocean-induced magnetic field. Keywords. Electromagnetics (numerical methods) – geomagnetism and paleomagnetism (geomagnetic induction) – history of geophysics (transport)
用全球海洋环流模型同化 GRACE 得出的海洋质量分布
影响因子：
4.4
作者：
Saynisch J;Bergmann-Wolf;Thomas
通讯作者：
Thomas