Analysing potential cliff erosivity from ERS SAR satellite imagery

This paper demonstrates a method to elucidate potential erosivity (PE) of c liff strata that fall within the radar shadow of European Remote Sensing (E RS) Synthetic Aperture Radar (SAR) imagery. ERS-1 imagery of cliff faces in Israel's Negev Desert that faced 'away' from the satellite look direction contained alternating grey/black stripes that corresponded to the sedimento logical units that make up the cliffs. High return values or digital number s (DN) relate to gently sloping surfaces with softer lithologies that yield higher rates of weathering. Conversely, lower return values (DN) represent steeper surfaces with harder lithologies that yield a slower rate of weath ering. Backscatter and Z-score values were extracted from the image to deri ve an index of PE for strata at the feature and sub-feature level. This met hod may be used to determine relative erosivity of cliff strata, compliment existing geological mapping techniques and refine topographical representa tion of cliff faces in existing digital elevation models (DEMs).