12.5.1.2. Microwave
In the microwave data, care should be taken in the shadow areas, smooth regions and areas disturbed by wind waves. Shadow areas do not yield any backscatter and are thus similar to ideal, smooth water surfaces. Flood in shadow areas can easily be remedied by masking out steep areas derived from the digital elevation model (DEM).
In addition to water, other surfaces like large roads, parking lots and especially airfields and runways can be smooth at radar wavelengths, and thus there is little or no backscatter. Using runways and roads from GIS database, we can be aware of potentially problematic areas and double check the likeliness of these structures being flooded.