This study analyzed the relationship between inundated area and actual water volume using data from satellites, including the Moderate Resolution Imaging Spectroradiometer (MODIS) and Gravity Recovery and Climate Experiment (GRACE) satellite systems. The results showed that using relatively simple assumptions for the flow of water, a clear relationship could be demonstrated between inundation ratio and water volume. In the Chao Phraya River basin, the spatial average of the converted data from MODIS showed good correlation with the water volume measured by GRACE. Since the method used in this study does not rely heavily on the characteristics of a specific region, it is expected the approach would be applicable on a global scale if the necessary data were available.
