Optimized mapping of flood extent and floodplain structures by radar EO-methods
Edith Stabel(1) and Ernst Löffler(1)
Today, river dynamics is strongly influenced by human activities in the catchment affecting the hydrological behaviour, but
also by activities in the floodplain. The knowledge in recent and historical river dynamics and the related morphological and
structural changes in the earths surface (e.g. sedimentation, accumulation, river bed movement) is one essential point
regarding the flood risk estimation and the vulnerability of the resources and structures. Operational earth observation (EO)
systems provide data to monitor and analyze both, the river dynamics and the small surface changes. Especially the radar
based systems and the interferometric data analysis approach are of high interest. With selected sites at the river Odra area,
we analyzed the potential of radar based EO-applications due to the detection of structural changes, validated by field work.
Within the work described, the coherence information became of high interest: On the one hand, it could be used to eliminate
misclassifications of the flood extent caused by double bounce scattering, corner reflection and smooth surfaces. On the other
hand the production of RGB's type interferometric signature (coherence, average, difference of tandem pairs) is a powerful
tool to visualize the flood dynamics in space and time but also the morphologic structures in the floodplain.
As conclusion, it is shown that the combined analysis of radar backscatter and coherence information will be very useful in
the flood application domain, especially with view to a risk and vulnerability mapping. In addition, the methods described will
support the collection of relevant base data claimed by the EU water framework directive.
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,