The role of satellite information in forecasting, modeling, and mapping the 2019 Mozambique flood

Abstract 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.