Acta Geodaetica et Cartographica Sinica ›› 2025, Vol. 54 ›› Issue (5): 805-818.doi: 10.11947/j.AGCS.2025.20240397

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The impact of environmental loading on nonlinear variations of 3D coordinate time series of GNSS stations in Sichuan and Yunnan region

Shunqiang HU1(), Kejie CHEN2,3(), Xiaoxing HE4, Hai ZHU2, Tan WANG5   

  1. 1.Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang 330022, China
    2.Department of Earth and Space Sciences, Southern University of Science and Technology, Shenzhen 518055, China
    3.Key Laboratory of Earthquake Forecasting and Risk Assessment, Ministry of Emergency Management, Shenzhen 518055, China
    4.School of Civil and Surveying & Mapping Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China
    5.China Earthquake Networks Center, Beijing 100045, China
  • Received:2024-09-23 Revised:2025-04-11 Online:2025-06-23 Published:2025-06-23
  • Contact: Kejie CHEN E-mail:husq@jxnu.edu.cn;chenkj@sustech.edu.cn
  • About author:HU Shunqiang (1991—), male, PhD, majors in GNSS coordinate time series analysis. E-mail: husq@jxnu.edu.cn
  • Supported by:
    Key Research and Development Program Project of Jiangxi Province(2024BBI91033);The National Natural Science Foundation of China(42364002)

Abstract:

Investigating the nonlinear variations in GNSS coordinate time series can obtain a high-precision GNSS velocity fields, which contribute to establish and maintain a dynamic Earth reference frame. Here, we used the 94 GNSS stations data over the period January 2011 to December 2022 at Sichuan and Yunnan region and calculated the environmental loading deformation associated with hydrological loading, atmospheric loading, and non-tidal ocean loading, which provided by the IMLS and GFZ, respectively. We quantitatively evaluates the nonlinear changes in the GNSS 3D coordinate time series using PRMS that the percentage of RMS change after environmental loading correction. Finally, the ICA model was carried to separate the nonlinear signals in the vertical GNSS coordinate time series. The results show that the environmental loading products provided by IMLS outperforms the GFZ. The hydrological loading and atmospheric loading significantly correct nonlinear changes in vertical GNSS coordinate time series, with an average PRMS values of 8.66% and 6.74%, respectively. In the horizontal north (N) component, the hydrological loading can weaken the nonlinear changes in the GNSS coordinate time series, with an average PRMS values of 2.07%; while the atmospheric loading will increase the nonlinear changes, with an average PRMS values of -0.22%. In the horizontal east (E) component, the hydrological loading increase the nonlinear changes, with an average PRMS values of -0.11%; while the effect of atmospheric loading correction is weak, with an average PRMS values of 0.22%. For the NEU components, the effect of non-tidal ocean loading correction is not obvious in nonlinear changes of GNSS coordinate time series, with an average PRMS values of 0.33%, -0.2%, and 0.63%, respectively. The correlation coefficients between the IC2 signal separated by the ICA method and the IMLS atmospheric loading deformation range from -0.68 to 0.71 (greater than 0.65 accounting for 73% of all GNSS stations), with an average value of 0.64, while the correlation coefficients between the IC4 signal and the hydrological loading deformation obtained by the GRACE/GRACE-FO model range from 0.55 to 0.79, with an average value of 0.69, indicating that the IC2 and IC4 signals may be related to the nonlinear changes caused by atmospheric loading and hydrological loading, respectively. Furthermore, it is necessary to correct nonlinear changes in GNSS coordinate time series using environmental loading products.

Key words: GNSS, Earth reference frame, environmental loading, nonlinear changes, ICA

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