Adler R., Gu G., Zhou N., Wu H., Matgen P., Galantowicz J., Schumann G., Yilmaz K.K.
Journal of Flood Risk Management, vol. 18, n° 1, art. no. e12843, 2025
The application and value of the Global Flood Monitoring System (GFMS) and various remote-sensing-based flood products are examined in the context of the severe flood event in Mozambique associated with Cyclone Idai in March 2019. Short-term forecasts of rainfall and flooding are shown to be useful and validated to some degree by satellite-based rainfall from the Global Precipitation Monitoring (GPM) Integrated Multi-satellitE Retrievals for GPM (IMERG) product. However, detailed validation of the satellite-based rainfall for this event is limited and examination of other similar cases indicates a possible underestimate at high rainfall amounts. GFMS inundation based on the IMERG rainfall and models are compared to Synthetic Aperture Radar (SAR) and other inundation estimates. Results indicate a generally good correspondence, but with the GFMS calculations underestimating the area of broad flooding, but overestimating in smaller streams. The GFMS underestimation compared to a SAR-based estimate in one particular area seems related to rainfall underestimation. Similar generally good results were found when comparing the GFMS calculations to the FloodScan passive microwave-based inundation. The various inundation estimates are available at different latencies and likely have different accuracies, indicating a need for integration of these types of information to provide the user community with the best consolidated information and in a timely manner.
