Geomagnetic field analysis—III. Magnetic fields on the core—mantle boundary
Geomagnetic field analysis—III. Magnetic fields on the core—mantle boundary
复制标题
地磁场分析——三、地核-地幔边界磁场
DOI：
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
J. Bloxham
中科院分区：
文献类型：
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作者：
D. Gubbins;J. Bloxham
摘要将以往应用于长期变化资料的随机反演方法应用于主要野外资料。需要对该方法进行调整：既使用线性数据，也使用非线性数据;在观测站数据中考虑到地壳成分;对先验信息的规定有所不同。要求模型应满足有限的下限欧姆加热的核心提供了强大的先验信息，并给出有限的误差估计在核幔边界。
新方法适用于1969.5和1980.0年代的数据。由此产生的场模型比其他模型复杂得多，例如外推到核心的IGRF模型，并显示出相当多的小尺度细节，根据误差分析，可以相信。
在每个历元计算北方半球的通量积分;两个历元之间的差异约为一个标准差，这表明偶极子的衰变是否与冻结通量假设一致的问题已经得到解决，有利于该假设。
Summary. The method of stochastic inversion, previously applied to secular variation data, is applied to main field data. Adaptations to the method are required: non-linear, as well as linear, data are used; allowance is made for crustal components in the observatory data; and the prior information is specified differently. The requirement that the models should satisfy a finite lower bound on the Ohmic heating in the core provides strong prior information and gives finite error estimates at the core—mantle boundary.
The new method is applied to data from the epochs 1969.5 and 1980.0. The resulting field models are very much more complex than other models, such as the IGRF models extrapolated to the core, and show considerable small-scale detail which, on the basis of the error analysis, can be believed.
The flux integral over the northern hemisphere is computed at each epoch; the difference between the two epochs is approximately one standard deviation, suggesting that the question as to whether the decay of the dipole is consistent with the frozen-flux hypothesis has been resolved in favour of the hypothesis.