1. Analysis of Ocean Tide Loading Displacement Correction for Long-Strip InSAR Measurements in Coastal Areas of France
- Author
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Mengrui Wang, Qijie Wang, Huayi Zhang, Weiwei He, Fengxian Xiao, and Jiachen Li
- Subjects
Long-strip insar ,ocean tide loading (OTL) displacement ,ocean tide model ,Ocean engineering ,TC1501-1800 ,Geophysics. Cosmic physics ,QC801-809 - Abstract
Ocean tide loading (OTL) is a spatial long-wavelength signal characterized by nonlinear variations. The significance of its impact on interferometric synthetic aperture radar (InSAR) measurements increases with increasing interferogram coverage area. Accurate OTL correction is crucial for improving the accuracy of wide-area InSAR deformation measurements. In this study, we evaluate the precision differences among multiple ocean tide models in western France. Subsequently, leveraging multiple same-track SAR images, we analyze the impact of OTL on InSAR interferograms across different spatial scope. Finally, we apply OTL correction to long-strip differential interferograms, and evaluate the impact of OTL correction using both the standard deviation (StdDev) and variogram of interferograms, and validate the significance of OTL correction through comparison with GPS. The results reveal that: First, as the spatial scope of InSAR measurements expands, the residual error produced by OTL in fitting differential interferograms using conventional BRF grows correspondingly. Second, applying OTL correction effectively reduces the long-wavelength errors caused by OTL in long-strip differential interferograms. When only the atmospheric delay is corrected, the StdDev decreases by 18%. Further application of OTL correction reduces the StdDev to 25%. Third, the long-wavelength impact of OTL on InSAR measurements exhibits a distance dependence; it may be negligible at spatial scope less than 100 km but can become comparable with the atmospheric delay at spatial scope exceeding 300 km. Finally, OTL correction effectively enhances the InSAR deformation accuracy. In certain cases, OTL correction mitigates the additional errors introduced by atmospheric delay correction.
- Published
- 2024
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