Research on the refinement algorithm of surface loading deformation based on Green’s function

Surface deformation calculations due to environmental loading typically rely on the Preliminary Reference Earth Model (PREM), which assumes a homogeneous and isotropic Earth structure, leading to noticeable errors. To enhance accuracy, the high-precision crustal model CRUST 1.0 is used to refine calculations of regional surface deformation caused by hydrological and non-tidal atmospheric loading. The improved model is applied to 27 Global Navigation Satellite System (GNSS) reference stations in the first phase of the Crustal Movement Observation Network of China (CMONOC), considering their geographical locations. Green’s functions are employed to compute surface deformation at each site. Results indicate relative discrepancies of 11.78% and 14.14% for non-tidal atmospheric and hydrological loading compared to PREM, with vertical deformation differences reaching an average of 18.95%. Additionally, the distinct spatial distribution characteristics of the relative differences in each direction indicate that the improved RPREM model is more responsive to the mass variations derived from Gravity Recovery and Climate Experiment (GRACE). The results suggest that the improved PRREM model demonstrates higher sensitivity to loading variations than the PREM model. Utilizing the enhanced method of calculating surface deformation through the utilization of Green’s function at the site could effectively reduce the calculation error caused by regional structure, leading to enhanced uniformity and isotropy of PREM.