Accounting for quiet-time magnetospheric field contributions in geomagnetic field modelling

IF 1.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Physics of the Earth and Planetary Interiors Pub Date : 2025-06-30 DOI:10.1016/j.pepi.2025.107411

Nils Olsen

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引用次数: 0

Abstract

Accurate modelling of Earth’s core and lithospheric magnetic field requires minimising the influence of contributions from ionospheric and magnetospheric currents. This study examines different approaches for accounting for quiet-time magnetospheric contributions in geomagnetic field modelling, with a focus on the magnetospheric ring current. Traditional indices, such as the

D_{st}

or the RC indices, have been widely used for this but exhibit limitations. The study explores variations of the RC index, incorporating ground-based observatory data from different latitude ranges, and evaluates their effect on geomagnetic field modelling. Additionally, approaches based on a combined analysis of ground and satellite data are assessed for their ability to provide a more accurate representation of magnetospheric contributions, going beyond its usual approximation by a uniform field (the so-called

P_{1}^{0}

-approximation). Results indicate that including mid-latitude ground observatory data and utilising higher spherical harmonic for describing magnetospheric contributions lead to improved geomagnetic field models and reduced data misfit.

Abstract Image

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在地磁场模拟中计算静时磁层场的贡献

要对地核和岩石圈磁场进行精确建模，就必须尽量减少电离层和磁层电流的影响。本研究考察了在地磁场模型中计算静时磁层贡献的不同方法，重点关注磁层环电流。传统的指数，如Dst或RC指数，已被广泛用于此，但显示出局限性。该研究结合了来自不同纬度范围的地面观测数据，探讨了RC指数的变化，并评估了它们对地磁场建模的影响。此外，对基于地面和卫星数据综合分析的方法进行了评估，因为它们能够提供更准确的磁层贡献表示，超越了通常的均匀场近似（所谓的p10近似）。结果表明，引入中纬度地面观测数据和利用更高的球谐来描述磁层贡献，可以改善地磁场模型，减少数据的不拟合。

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来源期刊

Physics of the Earth and Planetary Interiors 地学天文-地球化学与地球物理

CiteScore

5.00

自引率

4.30%

发文量

审稿时长

18.5 weeks

期刊介绍： Launched in 1968 to fill the need for an international journal in the field of planetary physics, geodesy and geophysics, Physics of the Earth and Planetary Interiors has now grown to become important reading matter for all geophysicists. It is the only journal to be entirely devoted to the physical and chemical processes of planetary interiors. Original research papers, review articles, short communications and book reviews are all published on a regular basis; and from time to time special issues of the journal are devoted to the publication of the proceedings of symposia and congresses which the editors feel will be of particular interest to the reader.