Analysis of ERS SAR coherence images acquired over vegetated areas and urban features
Synthetic Aperture Radar (SAR) coherence images were analysed over vegetated areas and urban features. Coherence images were formed from interferometric SAR data acquired 1 day or 35 days apart by two European Remote sensing Satellites (ERS). Forested areas are discriminated very well from cultivated fields using 1-day SAR coherence data taken in the winter when the temperatures were below freezing. This is because fields under these conditions decorrelate much less than forest. Open sandy fields gave high coherence for both winter and summer acquisitions. All vegetated areas experienced a strong temporal decorrelation over a 35-day period. This is mainly due to changing wind, precipitation and temperature conditions, but could also be due to vegetation growth or man-made changes. Many urban objects were found to decorrelate slowly with time, regardless of changing weather conditions.