Seasonal Effect on InSAR Derived DEMs

In the process Interferometric Synthetic Aperture Radar (InSAR) derived Digital Elevation Models (DEMs), coherence enhances the raw interferograms in order to achieve a good estimation of the difference in the optical paths related to topography. Furthermore, it is an important parameter qualifying the accuracy of the interferometric measurements. The aim of this study is to examine the effect of rainfall on repeat-pass InSAR derived DEM in different land cover by evaluating the quality of coherence product. In this study, we have found that the effect of rainfall and wind might be as important as baseline decorrelation on the production of coherence. For example, under the same condition of minimum temporal decorrelation, the tandem InSAR pair with longer baseline and zero rainfall obtains better coherence than other tandem pairs. On the other hand, under different conditions of temporal decorrelation, the tandem pairs with higher rainfall records preserve lower mean coherence value than the InSAR pair with 36 days time span even though these tandem pairs have similar or smaller baseline than the 36 days InSAR pair has.