Effect of the Unwrapping Process on the Correlations Among InSAR Differences for the Same Area

Differences among SAR interferograms (InSAR) represent an important tool for the measurement of natural and maninduced surface deformations. If not important terrain movements are observed during the considered time interval, largest differences are mostly interpreted in terms of atmospheric effects. Otherwise, smaller differences can be interpreted in terms of interseismic terrain landslides or other generic land cover or ground surface changes. In particular, significant correlations among InSAR differences and/or with the topography are reported in previous papers. In some cases, these are interpreted in terms of atmospheric or geological mechanisms. In this paper, a relationship between the unwrapping process and the correlations among InSAR and InSAR differences is observed. It is concluded that these correlations can be, at least partially, of non-geophysical origin, driven by computational procedures.