Observing Earth’s magnetic environment with the GRACE-FO mission

Stolle, Claudia; Michaelis, Ingo; Xiong, Chao; Rother, M.; Usbeck, T.; Yamazaki, Yosuke; Rauberg, Jan; Styp-Rekowski, Kevin

doi:10.1186/s40623-021-01364-w

Cited by 20 publications

(25 citation statements)

References 52 publications

(64 reference statements)

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“…In Antarctic regions close to the magnetic pole where the vertical magnetic field exceeds − 52, 974 nT, the magnetic data are saturated and have been flagged and discarded from the further analysis. The 12-bit digitization of the GRACE magnetometer data result in increased noise when analysing the data: the quantization noise produced by a N = 12-bit digitizer sampling in steps of size d results in a root-mean-squared (rms) noise (Schwartz 1980…”

Section: The Grace Magnetometer Measurementsmentioning

confidence: 99%

Magnetometer data from the GRACE satellite duo

Olsen

2021

Earth Planets Space

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This paper describes and discusses the preprocessing and calibration of the magnetic data taken by the navigational magnetometers onboard the two GRACE satellites, with focus on the almost 10 years period from January 2008 to the end of the GRACE mission in October 2017 for which 1-Hz magnetic data are available. A calibration of the magnetic data is performed by comparing the raw magnetometer sensor readings with model magnetic vector values as provided by the CHAOS-7 geomagnetic field model for the time and position of the GRACE data. The presented approach also accounts for magnetic disturbances produced by the satellite’s magnetorquer and for temperature effects, which are parametrized by the Sun incident angle. The root-mean-squared error of the difference between the calibrated data and CHAOS-7 model values is about 10 nT, which makes the GRACE magnetometer data relevant for geophysical investigations.

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Section: The Grace Magnetometer Measurementsmentioning

confidence: 99%

Magnetometer data from the GRACE satellite duo

Olsen

2021

Earth Planets Space

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“…As part of the attitude and orbit control system, the GRACE-FO mission carries magnetometers that aim to enhance the satellite's navigation. Stolle et al (2021) performed detailed calibration of the magnetic measurements from GRACE-FO. They showed that during times of geomagnetically quiet conditions, the mean magnetic residual to the geomagnetic model CHAOS-7 (Finlay et al 2020) is around 1 nT with standard deviations below 10 nT, which is remarkably good for a nonscience instrument.…”

Section: Grace-fo Mission and The Magnetic Measurementsmentioning

confidence: 99%

“…It confirms that after an appropriate calibration and characterization of artificial magnetic disturbances, the magnetic observations of GRACE-FO are valuable assets to investigate the natural variability of Earth's magnetic field. Details about the calibration and initial validation of GRACE-FO magnetic data are given in Stolle et al (2021).…”

Section: Grace-fo Mission and The Magnetic Measurementsmentioning

confidence: 99%

Correlation analysis of field-aligned currents from the magnetic measurements of GRACE follow-on mission

Xiong

Stolle

Michaelis

et al. 2021

Earth Planets Space

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In this study we performed a detailed analysis on the scale-size of field-aligned currents (FACs) at auroral latitudes, using the well-calibrated magnetic data from the non-dedicated magnetic field mission, Gravity Recovery and Climate Experiment Follow-On (GRACE-FO). With two spacecraft following each other, the GRACE-FO provides a good opportunity to identify the variation of FACs with different scale lengths. The results show that the auroral FACs can be classified into two groups: the small-scale ones, shorter than some tens of kilometers, dominated by kinetic Alfvén waves, are quite dynamic; and the large-scale ones, typically larger than 150 km, can be considered as quasi-static and persist longer than 1 min. The GRACE-FO observations also reveal that the small-scale FACs at the same location sometimes can persist over 25 s, e.g., around dusk and dawn hours, which is longer than the typical persistent period (10 s) of kinetic Alfvén waves as earlier reported. The FAC structures show clear magnetic local time dependence, with higher correlations between the spacecraft around dusk and dawn hours; lower correlations are found around midnight and lowest correlations around noon, implying that the small-scale FACs most frequently appear at the noon cusp region. Slightly better correlations of FACs between two spacecraft are found during local summer, and such seasonal dependence is dominated by the correlations of small-scale FACs at noon. However, further analysis shows that the small-scale FACs at noon have largest occurrence and intensity during local summer, which reveals that when interpreting the cross-correlation analysis the intensity of FACs needs to be taken into account. Graphical Abstract

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“…Together with other missions in this post-VAP era, the NextSat-1/ISSS can contribute useful information on the radiation belt to the space science community. In addition to the particle and cold plasma observations described above, magnetic field data from the onboard FGM are being calibrated by empirical geomagnetic field models, following Olsen et al (2020) and Stolle et al (2021). As soon as the calibration is finished, the magnetic field data will also be made available to the public.…”

Section: Accepted Articlementioning

confidence: 99%

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

et al. 2021

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Monitoring the Earth's radiation belt by Low-Earth-Orbit (LEO) satellites has a long history and complemented observations near the high-altitude equatorial plane. However, most of the previous LEO missions suffered from limitations in energy resolution, energy range, L-shell coverage, or the mission lifetime, which leave room for further improvement in this topic. Here we present multi-year (January 2019~February 2021) observations of energetic (0.03 MeV~1.8 MeV) electrons by the Korean NextSat-1 (altitude~575 km) with high energy resolution (0.006-0.4 MeV) and seamless L-shell coverage. For <80 keV electrons, the slot-region outer edge moves inward with increasing geomagnetic activity, which agrees with previous Van Allen Probes reports. The behavior is more conspicuous for lower-energy electrons. Latitudinal profiles of outer-belt electron flux are smoother equatorward of the geosynchronous footprint latitudes (|MLAT|~66 o ) than poleward. The NextSat-1 electron flux is positively correlated to geosynchronous observations, with the coefficient generally higher for higher electron energies. Also, both the geosynchronous and NextSat-1 data exhibit similar spectral indices close to -3 in the log-log space. All these results complement and expand previous knowledge on energetic electrons. The main findings are discussed in the context of existing literature.

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Observing Earth’s magnetic environment with the GRACE-FO mission

Cited by 20 publications

References 52 publications

Magnetometer data from the GRACE satellite duo

Magnetometer data from the GRACE satellite duo

Correlation analysis of field-aligned currents from the magnetic measurements of GRACE follow-on mission

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

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