摘要：The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission carries magnetometers that are dedi‑ cated to enhance the satellite’s navigation. After appropriate calibration and characterisation of artifcial magnetic disturbances, these observations are valuable assets to characterise the natural variability of Earth’s magnetic feld. We describe the data pre-processing, the calibration, and characterisation strategy against a high-precision magnetic feld model applied to the GRACE-FO magnetic data. During times of geomagnetic quiet conditions, the mean residual to the magnetic model is around 1 nT with standard deviations below 10 nT. The mean diference to data of ESA’s Swarm mission, which is dedicated to monitor the Earth’s magnetic feld, is mainly within ±10 nT during conjunctions. The performance of GRACE-FO magnetic data is further discussed on selected scientifc examples. During a magnetic storm event in August 2018, GRACE-FO reveals the local time dependence of the magnetospheric ring current signature, which is in good agreement with results from a network of ground magnetic observations. Also, derived feld-aligned currents (FACs) are applied to monitor auroral FACs that compare well in amplitude and statistical behav‑ iour for local time, hemisphere, and solar wind conditions to approved earlier fndings from other missions including Swarm. On a case event, it is demonstrated that the dual-satellite constellation of GRACE-FO is most suitable to derive the persistence of auroral FACs with scale lengths of 180 km or longer. Due to a relatively larger noise level compared to dedicated magnetic missions, GRACE-FO is especially suitable for high-amplitude event studies. However, GRACEFO is also sensitive to ionospheric signatures even below the noise level within statistical approaches. The combina‑ tion with data of dedicated magnetic feld missions and other missions carrying non-dedicated magnetometers greatly enhances related scientifc perspectives.
其他摘要：An amendment to this paper has been published and can be accessed via the original article.
