Applying Reconstructed Daily Water Storage and Modified Wetness Index to Flood Monitoring: A Case Study in the Yangtze River Basin

The terrestrial water storage anomaly (TWSA) observed by the Gravity Recovery and Climate Experiment (GRACE) satellite its successor GRACE Follow-On (GRACE-FO) provides a new means for monitoring floods. However, due to coarse temporal resolution of GRACE/GRACE-FO, understanding flood occurrence mechanisms short-term floods are limited. This study utilizes statistical model reconstruct daily TWS combining monthly observations with temperature precipitation data. reconstructed TWSA is utilized monitor catastrophic event that occurred in middle lower reaches Yangtze River basin 2020. Furthermore, compares vertical displacements eight Global Navigation Satellite System (GNSS) stations at grid scale. A modified wetness index (MWI) normalized potential (NDFPI) introduced compared situ streamflow assess their early warning. results show (TWS) area increases from June, reaching peak on 19 July, then receding till September. better captures changes scale MWI NDFPI based both exceed 90th percentile 7 days earlier than streamflow, demonstrating monitoring. Collectively, these findings suggest can serve as an effective tool