Improved Consistency of an Automated Multisatellite Method for Extracting Temporal Changes in Flood Extent

Malaysia is affected by floods almost every year. In this situation, high-frequency flood monitoring crucial so that timely measures can be taken. However, the low revisit time of satellites, as well occlusion cast clouds in optical images, limits frequency observation focused area. Therefore, study proposes utilising multisatellite data from satellites such Landsat 7, 8, and Moderate Resolution Imaging Spectroradiometer (MODIS), Synthetic Aperture Radar (SAR) images Advanced Land Observation Satellite (ALOS-2) Sentinel-1, to increase flood. The main objective was utilize Otsu image segmentation over both SAR satellite distinguish water nonwater areas each separately. For this, modified normalized difference index (MNDWI) for total dual-polarization backscatter were estimated. area has been divided into Universal Transverse Mercator (UTM) square-size grids 30 pixels, reprojected resampled with a pixel size 0.001° standardize map resolution. second assess potential fusion increasing consistency extraction. Two pairs same period covering event September 2017 Perlis, Malaysia, processed using 2D wavelet transform. Lastly, temporal changes integrated surface extent evaluated comparing output fused observed level Department Drainage Irrigation. results showed proposed model used estimate duration flood-related losses, especially ungauged or data-poor regions.