The use of triple collocation approach to merge satellite- and model-based terrestrial water storage for flood potential analysis

Terrestrial water storage anomaly (TWSA) retrieved from the Gravity Recovery and Climate Experiment (GRACE) mission can be used as a good indicator of flood potential, but it is limited to regional analysis due coarse resolution (?300 km). This study proposed an optimal least square merging scheme spatially downscale GRACE-based TWSA via integrating with model-based estimates on finer (0.125°) associated uncertainty estimates. products estimated GRACE, advanced Land Surface Model (LSM), reanalysis data were in process. Error uncertainties each input sets merged product calculated based triple collocation approach. The was subsequently compute potential index results compared against measured river discharge historical records. Results showed that provides better representation spatial variability at sub-regional scale relative along improved uncertainties. Merged also capability capturing events occurred local scales when