Jackson Andrew
School of Earth Sciences, University of Leeds, Leeds LS2 9JT, UK.
Nature. 2003 Aug 14;424(6950):760-3. doi: 10.1038/nature01879.
A large number of high-accuracy vector measurements of the Earth's magnetic field have recently become available from the satellite Oersted, complementing previous vector data from the satellite Magsat, which operated in 1979/80. These data can be used to infer the morphology of the magnetic field at the surface of the fluid core, approximately 2,900 km below the Earth's surface. Here I apply a new methodology to these data to calculate maps of the magnetic field at the core surface which show intense flux spots in equatorial regions. The intensity of these features is unusually large--some have intensities comparable to high-latitude flux patches near the poles, previously identified as the major component of the dynamo field. The tendency for pairing of some of these spots to the north and south of the geographical equator suggests they might be associated with the tops of equatorially symmetric columnar structures in the fluid, or their antisymmetric equivalents. The drift of the equatorial features may represent material flow or could represent wave motion; discrimination of these two effects based on future data could provide new information on the strength of the hidden toroidal magnetic field of the Earth.
最近，从奥斯特卫星获得了大量高精度的地球磁场矢量测量数据，补充了1979/80年运行的Magsat卫星先前的矢量数据。这些数据可用于推断位于地球表面以下约2900公里处的流体核心表面的磁场形态。在这里，我对这些数据应用一种新方法来计算核心表面的磁场图，这些图显示了赤道区域存在强烈的通量斑。这些特征的强度异常大——有些强度与极地附近的高纬度通量斑块相当，此前这些斑块被认为是发电机场的主要组成部分。其中一些斑点在地理赤道南北两侧配对的趋势表明，它们可能与流体中赤道对称柱状结构的顶部或其反对称等效结构有关。赤道特征的漂移可能代表物质流动，也可能代表波动；基于未来数据对这两种效应进行区分，可能会提供有关地球隐藏环形磁场强度的新信息。
