This paper presents the results of a study aiming to identify targets in Synthetic Aperture Radar (SAR) images having different properties in terms of microwave scattering and temporal stability using the interferometric SAR coherence and the Principal Component Analysis (PCA). Coherence maps used in this analysis are generated starting from a time series of Sentinel-1 images. A flat area in Padan plain (Italy), characterized by agricultural fields with different crops, urban settlements and water surfaces is chosen as study area.