In summer 2022 Pakistan was hit by catastrophic flooding. According to statements by the Pakistani government, the disaster reached “apocalyptic” dimensions, affecting a third of the country and 33 million people. As a fast post-event analysis of the Sentinel-1 flood maps as produced by the Copernicus Global Flood Monitoring (GFM) service showed, more than 30.000 km2 of land where inundated, of which more than 5.000 km2 stayed submerged for several weeks. These very high numbers support the dramatic depiction of the event by the Pakistani government and illustrate the usefulness of operational flood monitoring services to provide objective information in a fast manner. However, it must be noted that the comparably good coverage of the event by Sentinel-1 was quite lucky, thanks to a favourable orbit configuration and acquisition planning. In other words, this major flood event was well covered by Sentinel-1 while many others, particularly smaller events, are not adequately captured or missed at all. Therefore, it is important to improve the coverage and service quality by using more satellites and scale-up processing capabilities.

Fortunately, the upcoming ROSE-L mission that will be operated in tandem to Sentinel-1 and Sentinel-1 Next Generation offers many opportunities to elevate the quality of flood monitoring services to a new level. The first opportunity lies in the joint exploitation of the L- and C-band SAR imagery to improve the accuracy of the flood maps and extent the coverage to more densely vegetated and urban environments that cannot be monitored just with C-band data alone. The second opportunity lies in benefitting from the improved spatio-temporal coverage when using both satellite missions for the provision of flood maps. Therefore, the aim of the project is to prepare for ROSE-L and Sentinel-1 NG by developing scientific algorithms capable of ingesting nearinstantaneous L- and C-band SAR data and by investigating the benefits of the improved spatio-temporal coverage for capturing more and smaller flood events. This will be done by analysing the available worldwide Sentinel-1 flood archive as provided by GFM and using the L-band SAR data from the NISAR mission to be launched by NASA in 2024. The insights from this analysis will be shared with ESA that is currently fine-tuning the specifications of both ROSE-L and Sentinel-1 NG to best meet the equirements of diverse applications. The project will also respond to policies set forth by the European Commission's Green Deal by minimizing energy consumption and data storage by optimising the processing workflows and data management. Last but not least, the project will contribute to UN Sustainable Development Goals by investigating how the combined flood maps can be used to better assist flood impact assessments. This activity will help EODC, TU Wien and GeoVille to establish combined Sentinel-1 and ROSE-L services and prepare them for future ESA and EC tenders.