ABSTRACT
This study introduced large-scale flood monitoring by using Earth Observing System (EOS)/ Moderate Resolution Imaging Spectroradiometer (MODIS) data for the framework of emergency flood risk management and reduction in monsoon Asia. After the characterization of flood-detection indices, for example, Modified Land Surface Water Index (MLSWI), we improved a rapid and straightforward floodwater detection approach by using a hybrid floodwater detection algorithm coupled with the MLSWI and a digital elevation model (DEM)-based (Shuttle Radar Topography Mission (SRTM) DEM 15 s tracking algorithm. In Bangladesh flood, the detected flood areas (a 500 m spatial resolution) were verified by comparing with the Advanced Land Observing Satellite (ALOS) AVNIR-2 images (a 10 m spatial resolution) to be in moderate agreement (kappa coefficient = 0.57). As a result, the nationwide floodwater mapping was confirmed to be a globally applicable approach as well as transboundary river-basin level for effective emergency response in the early stage of a flood disaster, even before other data became available.
