| dc.description.abstract | Interferometric Synthetic Aperture Radar (InSAR) has been widely used to detect surface deformation such as earthquake, subsidence, and volcanic activities. Persistent Scatterer InSAR (PSInSAR) is one of the multi-temporal InSAR techniques to measure stable phase reflected by ground features, such as buildings, bridges, or other bright targets in radar wavelength. However, each SAR mission has its specified wavelength, resolution, revisit, and acquisition mode. Moreover, the scattering and penetration characteristics depend on the interaction with the target. Hence, this study proposes a novel concept to merge Sentinel-1 and TerraSAR-X PSInSAR results to leverage their individual advantages in land observations. Two experiments are conducted to explore the performance of the proposed method under different scenarios: Yunlin County with land subsidence and Taipei Basin with both natural and anthropogenic deformation. In our results, Yunlin area has a maximum cumulative subsidence reaching -51 mm in 2014 ~ 2016 in Line-Of-Sight (LOS) direction, while the root-mean-square error (RMSE) as compared against GNSS stations is 6.2 mm. Also, in Taipei Basin we observe a movement along the Shanchiao fault in the time series and slight settlement in the central of Taipei Basin. The correlation is 0.86 and RMSE is 6 mm in GNSS validation. We conclude that the mid-resolution SAR images calibrated by some temporally interleaved high-resolution images have better capability to observe land deformation that revising the overestimated S1 PSInSAR result, which shows a good agreement with on-site data, and to preserve detailed patterns. | en_US |