The use of hybrid data: PsInSAR, GNSS and levelling in the development of a modern model of vertical movements of the Earth's crust in Poland

The aim of this article is to present the first model in Poland of contemporary relative vertical movements of the Earth's crust, based on the integration of vertical movements determined from three sources: GNSS measurements (ASG-EUPOS), permanent PsInSAR scatterers from EGMS products, and double precise levelling measurements. Due to differences in the temporal and spatial resolution of the data, it was necessary to develop a consistent integration methodology. In the data merging process, an affine transformation was used to convert absolute vertical movements (GNSS and PsInSAR) to a relative system consistent with the levelling data. The InSAR data came from EGMS L2a products (after decomposition into a vertical component) and EGMS L3. The analysis showed that the optimal buffer radius for InSAR data in the study of micro-areas around GNSS stations is 0.3 km, and the use of the median as a representative value is statistically justified. The average transformation error for a single point was approximately 0.20 mm/yr. The final model was developed using the local polynomial method, and the results obtained provide a basis for further geodynamic studies and may be used in civil engineering and geological risk management.