LIU Bin, ZHOU Can, RAO Weilong, FENG Tengfei, CHEN Jinjin. Inversion of Regional Terrestrial Water Storage Using GNSS Observations Considering the Impact of Far-Field Hydrological Loading: A Case Study in the Sichuan-Yunnan Region[J]. Geomatics and Information Science of Wuhan University. DOI: 10.13203/j.whugis20240371
Citation:
LIU Bin, ZHOU Can, RAO Weilong, FENG Tengfei, CHEN Jinjin. Inversion of Regional Terrestrial Water Storage Using GNSS Observations Considering the Impact of Far-Field Hydrological Loading: A Case Study in the Sichuan-Yunnan Region[J]. Geomatics and Information Science of Wuhan University. DOI: 10.13203/j.whugis20240371
LIU Bin, ZHOU Can, RAO Weilong, FENG Tengfei, CHEN Jinjin. Inversion of Regional Terrestrial Water Storage Using GNSS Observations Considering the Impact of Far-Field Hydrological Loading: A Case Study in the Sichuan-Yunnan Region[J]. Geomatics and Information Science of Wuhan University. DOI: 10.13203/j.whugis20240371
Citation:
LIU Bin, ZHOU Can, RAO Weilong, FENG Tengfei, CHEN Jinjin. Inversion of Regional Terrestrial Water Storage Using GNSS Observations Considering the Impact of Far-Field Hydrological Loading: A Case Study in the Sichuan-Yunnan Region[J]. Geomatics and Information Science of Wuhan University. DOI: 10.13203/j.whugis20240371
Inversion of Regional Terrestrial Water Storage Using GNSS Observations Considering the Impact of Far-Field Hydrological Loading: A Case Study in the Sichuan-Yunnan Region
1 Highway Geological Hazard Early Warning Spatial Information Technology Hunan Provincial Engineering Laboratory, Changsha University of Science and Technology, Changsha 410114, China;
2 School of Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China;
3 Hunan Institute of Metrology and Test, Changsha 410014, China
Objectives: In the inversion of regional terrestrial water storage (TWS) using Global Navigation Satellite System (GNSS) data, it is common to expand the study area's boundaries to account for hydrological loading variations. However, effects of far-field hydrological loading on GNSS stations are often overlooked. When using full-range GNSS displacement data to constrain the TWS within the inversion region, the displacement information of the two does not completely correspond. Methods: We propose a GNSS regional TWS inversion method that considers far-field hydrological loading effects, focusing on the Sichuan-Yunnan region. Using Global Land Data Assimilation System (GLDAS) and Gravity Recovery and Climate Experiment (GRACE) data from January 2013 to May 2023, we calculate the displacements at GNSS stations in Sichuan-Yunnan due to hydrological loading from local, near, and far fields. Far-field displacement information is subtracted from the total GNSS displacements to refine the regional TWS inversion. Results: (1) With GLDAS data as the global hydrologic loading, the displacement amplitudes of GNSS sites from local, near, and far fields can reach 3.8 mm, 1.6 mm, and 2.3 mm, respectively. (2) Simulations using GLDAS-calculated site displacement show that de-remote field inversion results correlate most closely with GLDAS hydrologic loading scenarios, achieving a correlation of 0.98. (3) Extended inversion using GNSS data, after removing the far-field effect, shows that the average amplitude of TWS inversion results (GNSS(F_GL) and GNSS(F_GR)) is reduced by 19.1% and 25.4%, respectively. (4) The grid equivalent water height series in the two inversion accounting for far-field effects have a higher correlation with those in GRACE and GLDAS than in the extended inversion. Conclusions: In the inversion of TWS in Sichuan-Yunnan region using vertical GNSS observations, the displacements caused by far-field hydrological loading can not be ignored, and the far-field effect need be corrected while expanding the boundary inversion to ensure the accuracy of the inversion results.
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