Monitoring Land Surface Subsidence Using Radar Interferometry: The Challenges

SUMMARY Subsidence of the land surface is defined as the vertical surface movement due to the removal of subsurface support. This paper presents the differential interferometric synthetic aperture radar (DInSAR) results derived from the data of various SAR satellites, such as ERS-1/2, Radarsat-1 and JERS-1, for subsidence monitoring. One of the limitations of selecting the suitable interferometric pairs is the interferometric phase noise caused by the decorrelation between the two acquisitions of the interferometric pair. The level of phase noise depends upon both spatial and temporal baselines of the two acquisitions as well as the imaging resolution (pixel size). The phase noise is also subject to the variation of the dielectric characteristics of the objects on the land surface. The limits of the interferometric measurement are discussed in this paper by addressing the issues of the decorrelation and phase gradient.