Evaluation of Tidal Effect in Long-Strip DInSAR Measurements Based on GPS Network and Tidal Models

Abstract

A long-strip differential interferometric synthetic aperture radar (DInSAR) measurement based on multi-frame image mosaicking is currently the realizable approach to measure large-scale ground deformation. As the spatial range of the mosaicked images increases, the nonlinear variation of ground ocean tidal loading (OTL) displacements is more significant, and using plane fitting to remove the large-scale errors will produce large tidal displacement residuals in a region with a complex coastline. To conveniently evaluate the ground tidal effect on mosaic DInSAR interferograms along the west coast of the U.S., a three-dimensional ground OTL displacements grid is generated by integrating tidal constituents’ estimation of the GPS reference station network and global/regional ocean tidal models. Meanwhile, a solid earth tide (SET) model based on IERS conventions is used to estimate the high-precision SET displacements. Experimental results show that the OTL and SET in a long-strip interferogram can reach 77.5 mm, which corresponds to a 19.3% displacement component. Furthermore, the traditional bilinear ramp fitting methods will cause 7.2~20.3 mm residual tidal displacement in the mosaicked interferograms, and the integrated tidal constituents displacements calculation method can accurately eliminate the tendency of tidal displacement in the long-strip interferograms.

Mitigating Atmospheric Delays in InSAR Time Series: The DetrendInSAR Method and Its Validation

“…Furthermore, when focusing on a small area, the “trend” component, that is, ionospheric delays, turbulent atmospheric delays, and other unmodeled long‐wavelength signal and errors, can be approximated by a spatial position‐dependent polynomial of low order. Note that the unmodeled long‐wavelength signals may be due to inaccurate orbits, solid Earth or ocean tides (Peng et al., 2022), and plate motions (Stephenson et al., 2022) across the entire SAR image. Below, we provide mathematical expressions associated with the a‐priori information of the trend and the DEM‐correlated components, as well as the deformation at the Earth's surface.…”

Editorial for Special Issue “Ground and Structural Deformations Monitoring Systems Integrating Remote Sensing and Ground-Based Data”

“…Peng et al [16] have proposed a calculation method to evaluate the ground tidal effect on DInSAR interferograms mosaic along the west coast of the US. The authors analyzed long strip differential interferograms, integrating the tide displacement measured by 1038 GPS stations of the Plate Boundary Observation (PBO) network (data from 2014 to 2019), the FES2014+osu.usawest model and the Solid Earth Tide (SET) model in the 2010 IERS Convention.…”