Numerical models of the geodynamo and observational constraints
Numerical models of the geodynamo and observational constraints
复制标题
地球发电机数值模型和观测约束
DOI：
10.1029/2000gc000062
复制
发表时间：
2000
期刊：
影响因子：
3.7
通讯作者：
V. Courtillot
中科院分区：
文献类型：
--
作者：
E. Dormy;J. Valet;V. Courtillot
在过去的几年里，出现了大量的地球发电机的数值模拟。与此同时，新的和旧的地磁，古地磁和古地磁观测已被解释为实际的地磁特征，并用作发电机模型的约束。当然，模型预测应该根据地磁场的实际特征进行测试。尽管模拟中使用的参数值与地球的估计值之间存在巨大差异（有时超过10亿），但有趣的是，许多可用的模拟成功地产生了具有较弱非偶极结构的大部分轴向偶极磁场，与地磁场的一阶特征一致。然而，当考虑更精细的特征时，存在显著的差异，并且实际上未能产生一些基本的特征。在本文中，我们首先回顾了迄今为止获得的数值结果，然后我们试图总结哪些来自观测数据集的场特征可以被认为是稳健的。简单的标准，用于评估的置信度，可以放置在每个数据的基础上，我们大概特征地磁功能分为三类（强大的，有争议的，不太可能）。我们的结论是，数值模型应说明了一些关键的“预测”，平均超过至少10偶极扩散时间。这些预测应仅针对稳健观测子集进行检验。有争议的意见应等待进一步证实。
The past few years have seen the emergence of a large number of numerical simulations of the geodynamo. In parallel, both new and old geomagnetic, archeomagnetic, and paleomagnetic observations have been interpreted as actual geomagnetic features and used as constraints for dynamo models. Naturally, model predictions should be tested against actual characteristics of the geomagnetic field. Despite huge differences (sometimes in excess of a billion) between the values of parameters used in the simulations and those estimated for the Earth, it is intriguing that many available simulations succeed in producing largely axial dipolar magnetic fields with weaker nondipolar structures, in agreement with the first‐order characteristics of the geomagnetic field. Yet, when considering finer characteristics, there are significant differences, and failures to actually produce a number of fundamental characteristic features. In this presentation, we first review numerical results obtained to date, then we attempt to summarize which field characteristics derived from observational data sets can be considered robust. On the basis of simple criteria used to evaluate the degree of confidence that can be placed in each datum, we sort presumably characteristic geomagnetic features into three categories (robust, controversial, and unlikely). We conclude that numerical models should be illustrated with a number of key “predictions,” averaged over at least 10 dipole diffusion times. These predictions should be tested against the subset of robust observations only. Controversial observations should await additional confirmation.