Verlag der Österreichischen Akademie der Wissenschaften

Abstract:
Remote sensing and geographic information technologies are widely used in various aspects of the humanitarian sector’s activities. In the surface water mapping domain, Earth Observation plays a central role, enabling action at the level of disaster response as well as in preventive risk analysis. Most methodologies, however, rely on optical image analysis techniques that are not operational in cloudy conditions, that typically occur during the rainy season. In this article, we present a methodology that exploits SAR data exclusively. Being acquired in the microwave spectrum, SAR can operate irrespective of the weather and time of day. As a use case, we demonstrate the possible intersection of surface water layers with population and VGI data, which can provide enhanced information concerning displaced people and accessibility. The study area is the administrative unit level 3 of Pibor, South Sudan, which is reported to be particularly challenging in terms of logistics as well as for its environmental conditions. The results cover a multi-temporal dataset from 2017 to 2021, and a cross-validation is provided for a selected date showing an overall accuracy of 88.74% for the relevant surface water layer.