SChina20: A Stable Geodetic Reference Frame for Ground Movement and Structural Deformation Monitoring in South China

Abstract

We have established a stable regional geodetic reference frame, designated as SChina20, using approximately 10-year observations (2010–2019) at 40 Global Navigation Satellite System (GNSS) sites in South China. The regional reference frame is tied to the International GNSS Service (IGS) Reference Frame 2014 (IGS14) at epoch 2020.0. The primary products from this study are seven parameters for transforming the positional time series from IGS14 to SChina20 and a seasonal model for predicting vertical land surface displacements in South China. The frame stability of SChina20 is 0.4 mm/year in all three directions. We suggest that the scope of usage of SChina20 is spatially limited to the South China region and temporally limited to the 25-year time window from 2000 to 2025. We have also established a local-scale reference frame for the Hong Kong–Zhuhai–Macau (HZM) area, designated as HZM20. Applications of SChina20 in delineating urban subsidence and landslide are demonstrated in this article. SChina20 will be updated every few years to mitigate degradation of the frame stability over time and to synchronize with future updates of the IGS reference frame.