Slow magnetic Rossby waves in the Earth's core
Slow magnetic Rossby waves in the Earth's core
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DOI：
10.1002/2015gl064733
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发表时间：
2015-08-28
影响因子：
5.2
通讯作者：
Teed, R. J.
中科院分区：
文献类型：
--
作者：
Hori, K.;Jones, C. A.;Teed, R. J.
长期变化的向西漂移分量很可能是背景平均流上的波浪信号。通过分离波和平均流的贡献，我们可以推断出核心内磁场的“隐藏”方位角部分的强度。我们探讨了发电机模拟中常见的向西漂移的起源，并表明它以慢磁Rossby波的速度传播，相对于平均纬向流。我们的研究结果表明，这样的波可以激发在地球的核心，波的传播可能确实发挥了一定的作用，在纵向漂移，特别是在高纬度的波分量是相对较强的，赤道向西漂移的平均流量占主导地位。我们讨论了一个潜在的推断RMS环向场强度在地球的核心从观测到的漂移率。
The westward drift component of the secular variation is likely to be a signal of waves riding on a background mean flow. By separating the wave and mean flow contributions, we can infer the strength of the "hidden" azimuthal part of the magnetic field within the core. We explore the origin of the westward drift commonly seen in dynamo simulations and show that it propagates at the speed of the slow magnetic Rossby waves with respect to a mean zonal flow. Our results indicate that such waves could be excited in the Earth's core and that wave propagation may indeed play some role in the longitudinal drift, particularly at higher latitudes where the wave component is relatively strong, the equatorial westward drift being dominated by the mean flow. We discuss a potential inference of the RMS toroidal field strength within the Earth's core from the observed drift rate.