Temporal analysis of terrain subsidence by means of sparse SAR differential interferometric measurements

摘要

Synthetic aperture radar (SAR) differential interferometry allows, in principle, to measure very small movements of the terrain. Main limitations of this technique include decorrelation noise and atmospheric artifacts that can affect SAR differential interferograms. In this paper we show that the problem of decorrelation noise can be efficiently faced by using a new phase unwrapping approach that allows to process sparse data, and that the impact of atmospheric artifacts can be minimized by performing a temporal analysis of the deformations observed in successive SAR differential interferograms. Also, in this study we show that it is possible to perform a temporal analysis of slow terrain movements by using a rather limited number of ERS SAR data set and low precision topographic information. As an application of the proposed technique, the subsidence phenomena occurring in Bologna (Italy) and in the surrounding area from 1992 to 1999 are analyzed.