Dataset of a novel tidal model for long-strip DInSAR measurement by integrating tidal constituent estimation of the GPS network and empirical models
A long-strip synthetic aperture radar interferometric (InSAR) measurement based on multiframe image mosaicking is currently the realizable approach to measure large-range ground deformation. As the spatial range of the mosaicked images increases, the degree of ground effects are more significant, and using empirical global ocean tidal models or plane fitting to correct the OTL displacement will produce large errors in a region with a complex coastline. By integrating the Q1, O1, N2, and M2 constituents of a GPS reference station network and the P1, K1, and K2 constituents of an empirical global/regional ocean tidal model, the three-dimensional OTL displacements for high-precision DInSAR measurement is calculated, which can improve the accuracy of the OTL correction along the LOS direction by 10.4% in a complex coastline area. Meanwhile, the proposed OTL correction method and a solid earth tide (SET) model are used to estimate the ground tidal displacements in coastal long-strip differential interferograms. Experimental results show that the ground tidal displacements can reach 77.5 mm. If the bilinear ramp fitting method is used in a coastal long-strip interferogram, the residual of the tidal displacement is up to 20.3 mm, the novel OTL correction method and SET model can minimize the standard deviation (StdDev) of a differential interferogram by 19.3%, its major improvement region is the coastal area where the OTL displacement is more than 10~17 mm and the tendency of tidal displacement in long-strip interferograms can be accurately eliminated, which proves that the novel tidal method correction has high spatial accuracy.
1. Improvement of the empirical ocean tide model using kinematic PPP OTL estimation
According to tidal harmonic function and phasor construction, the tidal constituent displacement determined based on a GPS reference sites network and an empirical tidal model can be blended to estimate the OTL displacement measured in long-strip differential interferograms.
2. Removal of tide displacements in a long-strip Sentinel-1 differential interferogram
Using the ICAMS advanced atmospheric correction algorithm based on the ECMWF ERA-5 global atmospheric model (Cao et al., 2021), SET and OTL correction of the novel tidal model to correct the atmospheric delay error (especially for long-wavelength and topography-related atmospheric delay errors) and tidal displacements in the long-strip differential interferograms gradually and then bilinear ramp fitting was performed to eliminate the orbital error residuals.
Step1. The phasors of the tidal constituents estimated from kinematic PPP time series, which are saved in GPSPPPphasor.mat
Step2. The phasors of the tidal constituents estimated by empirical FES2014b+usawest.osu tidal model, which is saved in Modelphasor.mat
Step3. The predicted phasors of the tidal constituents Q1,O1,N2,M2 of the GPS reference sites network based on the spatial variation characteristics of the phasors of the tidal model, which is saved in GPSPPPphasor_predicQ1O1N2M2.mat
Step4. The original differential interferograms are saved in DInSAR.mat, the original differential interferogram after atmospheric delay error correction; are saved in DInSAR_Atmos.mat
Setp5. The original differential interferograms after atmospheric delay error, OTL and SET correction can be calculated by the corresponding matrix in DInSAR_Atmos.mat+OTLDInSAR.mat+SETDInSAR.mat