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

我们建议在年代际至次年代际尺度上详细研究全球地磁的长期变化。第一步将是扩展最近对1980年至2000年地球磁场长期变化的研究，该研究以前所未有的细节描述了两次所谓的地磁突变，即长期变化的快速变化，并导致探测到其他内部起源的短周期变化。将模型周期延长到1960年至2005年，将包括更多的地磁震动，并确认短周期变化的起源。我们进一步打算基于多个在轨卫星（即Orsted、CHAMP和SAC-C）的同时测量连续模拟长期变化。作为该项目的第一步，得到的模型将用于：1)模拟核-地表流动，2)研究核-地幔边界地磁跳变的时空结构，3)研究短周期长期变化特征的分布和来源。作为一个副作用，我们将能够为IGRF 2005和DGRF 2005提交候选模型。

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.