View angle importance of SAR satellite imageries for mapping areas susceptible to floods: A case study of Kumamoto Prefecture, Japan

Abstract

Natural hazards including landslides, flash floods, earthquakes and hurricanes have been constituted a significant problem in many countries. Kumamoto Prefecture in Japan was selected as the study area in the current research. One of the most considerable natural hazards in the study area is flood. Without using any automated classifier, this paper aims to map flooded areas in the region using synthetic aperture Radar (SAR) imagery of ALOS-2 PALSAR-2. A total number of six satellite imageries (before and right after the events) were collected. Using Sentinel application platform (SNAP) software the images were corrected, stacked and combined in order to map flooded areas. Results indicate that this kind of flood mapping is precise, fast and easy to use. This paper can be helpful to policy and decision makers in order to map flooded areas immediately, especially when we need a quick action for settling camps for evacuees during flooding days.