Decadal and subdecadal secular variation of the Earth`s magnetic field deduced from ground based measurements and multiple satellite measurements

我们建议详细研究全球地磁在十年到亚十年尺度上的长期变化。第一步将是最近对1980年至2000年地球磁场长期变化的研究的扩展，这项研究导致对两个所谓的地磁突变--长期变化的快速变化--进行了前所未有的详细描述，并导致发现了内部起源的其他短期变化。将模型周期延长到1960年至2005年，将包括更多的地磁突变，并确认短周期变化的来源。我们还打算根据对一颗以上在轨卫星(即Orsted、CHAMP和SAC-C)的同时测量，持续模拟长期变化。作为本项目的第一步，所建立的模型将用于：1)核-表面流动的模拟，2)核幔边界地磁跳跃的时空结构研究，3)短期长期变化特征的分布和来源的研究。作为一个副作用，我们将能够提交IGRF 2005和DGRF 2005的候选模型。

We propose a detailed study of global geomagnetic secular variation on the decadal to sub-decadal scale. The first step will be an extension of a recent examination of the secular variation of the Earth's magnetic field from 1980 to 2000, which resulted in the description of two so-called geomagnetic jerks, rapid changes of secular variation, in unprecedented detail and led to the detection of other short-period variations of internal origin. Extending the model period to 1960 to 2005 will include several more geomagnetic jerks and confirm the origin of the short-period variations. We further intend to continuously model secular variation based on simultaneous measurements of more than one satellite in orbit, namely Orsted, CHAMP and SAC-C. The models derived as first step of this project will then be used for: 1) modelling of core-surface flow, 2) investigation of the spatio-temporal structure of geomagnetic jerks at the core-mantle boundary, 3) investigation of the distribution and source of short-period secular variation features. As a side-effect, we will be able to submit candidate models for the IGRF 2005 and the DGRF 2005.