Decadal and subdecadal secular variation of the main geomagnetic field

我们建议研究1980-2000年期间的详细长期变化。这将通过利用所有可用数据同时模拟主场和长期变化来实现。时间间隔被高质量的卫星矢量数据“夹住”，这些数据来自1980年的Magsat和1999-2000年的Orsted/CHAMP。所有可获得的数据将在这段时间内进行审查，特别是在永久磁观测站和通过重复调查记录的长期变化。将特别注意重新审查POGS数据，试图从这些数据中提取一些矢量信息。所导出的模型将用于各种科学研究，包括1)考虑“地磁震动”，2)模拟核-表面流动，以及3)检查岩石圈场可能的时间依赖性。它们也适用于考虑外部磁场的影响。这项研究将作为跳板，为2005年IGRF、1995年和2000年DGRF提交候选模型。

We propose to examine the detailed secular variation over the period 1980-2000. This will be achieved by simultaneous modelling of the main field and secular variation using all available data. The time interval is "bookended" by high-quality satellite vector data, from Magsat in 1980, and Orsted/CHAMP in 1999-2000. All available data will be examined for the intervening period, especially secular variation recorded at permanent magnetic observatories and by repeat surveys. Particular attention will be paid to a re-examination of POGS data, with an attempt to extract some vector information from this data. The models derived will be used in various scientific studies including 1) consideration of "geomagnetic jerks", 2) modelling of core-surface flow, and 3) examination of possible time dependence of the lithospheric field. They will also be appropriate for considering the influence of external magnetic fields. The study will be used as a springboard towards submitting candidate models for IGRF 2005, and DGRF 1995 and 2000.