Accuracy evaluation of flood monitoring based on multiscale remote sensing for different landscapes

Floods are one of the most widespread and severe natural disasters. Then, evaluating the accuracy of multiscale remote sensing for flood monitoring is an essential research topic. In this study, floodwater boundary was obtained for application of the mechanism-based upscaling method and NDWI water extraction method. Floodwater extraction was simulated and its accuracy was analyzed for different spatial extents, spatial resolutions, landscape patterns and water body proportions at eight floodplains in China. The regional accuracy gradually increased with the spatial extent when the spatial resolution was constant and decreased with the spatial resolution when the spatial extent was constant. The water extraction accuracy showed a significant correlation with the water body proportion and water landscape pattern indices. The relative error of the water extraction had a strong positive correlation with the complexity of the patch shape and a strong negative correlation with the patch aggregation and connectivity and the water body proportion. Therefore, it may be concluded that different spatial resolutions of remotely sensed images should be selected according to differences in the water landscape patterns of regions to obtain results with the required water body extraction accuracy for regional flood monitoring in China.