Assessing the Performance of GRACE-FO KBR and LRI in Detecting Mass Changes Using Along-Orbit Range-Accelerations

authored by: Zitong Zhu, Changqing Wang, Yihao Yan, Yuhao Xiong, Qinglu Mu, Haoming Yan, Zizhan Zhang
Abstract: Gravity Recovery and Climate Experiment Follow-On is equipped with two inter-satellite ranging systems, notably the K-Band ranging (KBR) and the more precise Laser Ranging Interferometer (LRI), which enable the detection of variations in Earth's gravity. Assessing the differences between KBR and LRI is beneficial for understanding the performance of future LRI-only gravity satellite missions. However, due to limitations imposed by temporal aliasing errors, the advantages of LRI over KBR for monthly gravity field solutions are not clearly discernible. The along-orbit range-accelerations directly reflect the mass variations, providing a new way to evaluate the differences between LRI and KBR. Therefore, we selected different frequency bands and time scales to compare the along-orbit range-accelerations of KBR and LRI from 2019 to 2021. Analyzing the spatiotemporal-averaged along-orbit data, the results indicate a systematic difference between KBR and LRI, with a scale factor of about 0.977 over the selected 92 basins, while the scale factor is lower over oceanic regions. A comparison of the instantaneous along-orbit data for KBR and LRI reveals that the noise level of LRI in the [15.8–21 mHz] band is at least one order of magnitude lower than that of KBR. After simulating instrument noise, model errors, and time-variable signals, it was determined that KBR noise is likely the primary factor contributing to the systematic difference in capturing temporal signals between LRI and KBR. In addition, regions with a low signal-to-noise ratio (SNR) are more susceptible to noise, which diminishes the correlation between KBR and LRI along-orbit data.
Organisation(s): Institute of Geodesy
External Organisation(s): CAS - Innovation Academy for Precision Measurement Science and Technology (APM)
University of the Chinese Academy of Sciences (UCAS)
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
Sun Yat-Sen University
Huaihai Institute of Technology
Hubei Luojia Laboratory
Type: Article
Journal: Journal of Geophysical Research: Solid Earth
Volume: 130
ISSN: 2169-9313
Publication date: 16.06.2025
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Geophysics, Geochemistry and Petrology, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous)
Electronic version(s): https://doi.org/10.1029/2024JB029428 (Access: Closed)
: Details in the research portal "Research@Leibniz University"

BibTeX

@article{17344c3dc7f14dcbb86963c28326d518,
title = "Assessing the Performance of GRACE-FO KBR and LRI in Detecting Mass Changes Using Along-Orbit Range-Accelerations",
abstract = "Gravity Recovery and Climate Experiment Follow-On is equipped with two inter-satellite ranging systems, notably the K-Band ranging (KBR) and the more precise Laser Ranging Interferometer (LRI), which enable the detection of variations in Earth's gravity. Assessing the differences between KBR and LRI is beneficial for understanding the performance of future LRI-only gravity satellite missions. However, due to limitations imposed by temporal aliasing errors, the advantages of LRI over KBR for monthly gravity field solutions are not clearly discernible. The along-orbit range-accelerations directly reflect the mass variations, providing a new way to evaluate the differences between LRI and KBR. Therefore, we selected different frequency bands and time scales to compare the along-orbit range-accelerations of KBR and LRI from 2019 to 2021. Analyzing the spatiotemporal-averaged along-orbit data, the results indicate a systematic difference between KBR and LRI, with a scale factor of about 0.977 over the selected 92 basins, while the scale factor is lower over oceanic regions. A comparison of the instantaneous along-orbit data for KBR and LRI reveals that the noise level of LRI in the [15.8–21 mHz] band is at least one order of magnitude lower than that of KBR. After simulating instrument noise, model errors, and time-variable signals, it was determined that KBR noise is likely the primary factor contributing to the systematic difference in capturing temporal signals between LRI and KBR. In addition, regions with a low signal-to-noise ratio (SNR) are more susceptible to noise, which diminishes the correlation between KBR and LRI along-orbit data.",
keywords = "along-orbit range-acceleration, GRACE-FO, inter-satellite ranging system, mass change, systematic difference",
author = "Zitong Zhu and Changqing Wang and Yihao Yan and Yuhao Xiong and Qinglu Mu and Haoming Yan and Zizhan Zhang",
note = "Publisher Copyright: {\textcopyright} 2025. American Geophysical Union. All Rights Reserved.",
year = "2025",
month = jun,
day = "16",
doi = "10.1029/2024JB029428",
language = "English",
volume = "130",
journal = "Journal of Geophysical Research: Solid Earth",
issn = "2169-9313",
publisher = "John Wiley and Sons Inc.",
number = "6",
}