Extending comprehensive models of the Earth's magnetic field with Orsted and CHAMP data
Extending comprehensive models of the Earth's magnetic field with Orsted and CHAMP data
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DOI：
10.1111/j.1365-246x.2004.02421.x
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发表时间：
2004-11-01
影响因子：
2.8
通讯作者：
Purucker, ME
中科院分区：
文献类型：
--
作者：
Sabaka, TJ;Olsen, N;Purucker, ME
使用一种全面的方法推导出了静止时间近地磁场的新模型，其中不仅包括POGO和Magsat卫星数据，还包括Orsted和CHAMP卫星的数据。由此产生的模型显示了很大的改进，其前任在源的完整性，时间跨度和参数的降噪。由于其良好的分离场和1960年至2002年中期的扩展时域，该模型能够检测到该框架内的已知地磁急动序列，并为1997年左右的感兴趣事件提供证据。由于所有来源都是综合估计的，因此在模型的岩石圈表示中发现了通常用其他方法过滤掉的有趣的南北特征，例如南大西洋扩张脊和安第斯俯冲带线理。此外，这岩石圈领域表现出显着更少的噪音比以前的模型，作为改进的数据选择的结果。卫星所经过的F区电流现在被视为位于纬向平面内，而不是纯粹的径向。结果是一致的，以前发现的磁卫星，但在Orsted高度的分析显示，令人兴奋的证据表明，赤道电射流相关的赤道电流可能接近卫星下方。除了模型，一种新的分析技术已经开发出来，以推断一个特定的数据子集解决的模型参数状态的一部分。事实证明，这对诊断Magsat矢量数据中特殊人为现象的原因非常有用，这种人为现象似乎表明矢量磁力计中存在小的未对准偏差。
A new model of the quiet-time, near-Earth magnetic field has been derived using a comprehensive approach, which includes not only POGO and Magsat satellite data, but also data from the Orsted and CHAMP satellites. The resulting model shows great improvement over its predecessors in terms of completeness of sources, time span and noise reduction in parameters. With its well separated fields and extended time domain of 1960 to mid-2002, the model is able to detect the known sequence of geomagnetic jerks within this frame and gives evidence for an event of interest around 1997. Because all sources are coestimated in a comprehensive approach, intriguing north-south features typically filtered out with other methods are being discovered in the lithospheric representation of the model, such as the S Atlantic spreading ridge and Andean subduction zone lineations. In addition, this lithospheric field exhibits significantly less noise than previous models as a result of improved data selection. The F-region currents, through which the satellites pass, are now treated as lying within meridional planes, as opposed to being purely radial. Results are consistent with those found previously for Magsat, but an analysis at Orsted altitude shows exciting evidence that the meridional currents associated with the equatorial electrojet likely close beneath the satellite. Besides the model, a new analysis technique has been developed to infer the portion of a model parameter state resolved by a particular data subset. This has proven very useful in diagnosing the cause of peculiar artefacts in the Magsat vector data, which seem to suggest the presence of a small misalignment bias in the vector magnetometer.