Analysing potential cliff erosivity from ERS SAR satellite imagery

This paper demonstrates a method to elucidate potential erosivity (PE) of cliff strata that fall within the radar shadow of European Remote Sensing (ERS) 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 sedimentological units that make up the cliffs. High return values or digital numbers (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 weathering. Backscatter and Z-score values were extracted from the image to derive an index of PE for strata at the feature and sub-feature level. This method may be used to determine relative erosivity of cliff strata, compliment existing geological mapping techniques and refine topographical representation of cliff faces in existing digital elevation models (DEMs).