A Phase-Based InSAR Tropospheric Correction Method for Interseismic Deformation Based on Short-Period Interferograms

The new generation of synthetic aperture radar (SAR) satellites is serving our long-standing demand for high-resolution crustal deformation over various scales. However, the reliability of interferometric SAR (InSAR) measurements is still limited by varying tropospheric conditions between acquisitions, especially when mapping slow-deforming interseismic deformation. We propose here a new phase-based approach for mapping interseismic deformation using short-period interferograms. Our method formulates the InSAR phase after topographic correction as the sum of three components: 1) spatiotemporally varied turbulent tropospheric phase; 2) topography-correlated stratified tropospheric phase; and 3) interseismic-related deformation assumed to be accumulated at a constant rate. We simultaneously solve for the parameters in the model to avoid overestimating the tropospheric phases, especially when interseismic deformation and tropospheric delays are both coupled with elevation in space. Synthetic tests and practical applications to the easternmost Altyn Tagh fault demonstrate that the new method can effectively recover the small-amplitude interseismic deformation caused by fault motion even when the interferograms are dominated by strong tropospheric delays.