Co-estimation of the Earth main magnetic field and the ionospheric variation field

• Applicants: Professor Dr. Matthias Holschneider; Professorin Dr. Claudia Stolle, since 9/2015
• Subject Area: Geophysics
• Term: from 2013 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 237378001

The aim of this project is to co-estimate models of the core and ionosphere magnetic fields, with the longer-term view of building a “comprehensive” model of the Earth’s magnetic field. In this first step we would like to take advantage of the progresses made in the understanding of the ionosphere by global M-I-T modelling to better separate the core and ionospheric signals in satellite data. The magnetic signal generated in the ionosphere is particularly difficult to handle because satellite data provide only information on a very narrow local time window at a time. To get around this difficulty, we would like to apply a technique derived from assimilation methods and that has been already successfully applied in outer-core flow studies. The technique relies on a theoretical model of the ionosphere such as the Upper Atmosphere Model (UAM), where statistics on the deviations from a simple background model are estimated. The derived statistics provided in a covariance matrix format can then be use directly in the magnetic data inversion process to obtain the expected core and ionospheric models. We plan to apply the technique on the German CHAMP satellite data selected for magnetically quiet times. As an output we should obtain a model of the ionospheric magnetic variation field tailored for the selected data and a core-lithosphere field model where possible leakage from ionospheric signals are avoided or at least reduced. The technique can in theory be easily extended to handle the large-scale field generated in the magnetosphere.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1488: Planetary Magnetism (PlanetMag)
• Participating Person: Dr. Matthias Förster
• Ehemaliger Antragsteller: Professor Vincent Lesur, Ph.D., until 8/2015