GFM timeliness: < 8-hour lag from satellite data acquisition to flood map production
A key user requirement for the GFM product is the timeliness for generating the GFM product output layers of worldwide flood information. The practical experience of the entire GFM consortium has been made available to guarantee a product timeliness less than or equal to 8 hours, for all Sentinel-1 GRD scenes that become available on the ESA data hubs within 5 hours. This paramount requirement is ensured via the following measures:
GFM service availability: 24/7/365 / > 99% / global coverage
Guaranteed service availability of the GFM product is facilitated through EODC’s Sentinel-1 processing operations expertise (begun in 2014) which is regularly assessed by the ESA mission reports. These lessons learned have been used to implement a completely independent IT infrastructure for the CEMS GFM system operations. The operations are also organized through redundant 24/7 production coordinator staff availabilities, such that a 99% service availability is guaranteed.
GFM thematic accuracy: 90%+ accuracy of flood mapping
According to the general GFM product specifications (European Commission, 2020), the thematic accuracy of the Sentinel-1 observed flood and water extent output layers is required to reach a target threshold Critical Success Index (CSI) of 70-80%. Based on multiple test-cases, the GFM product has been shown to achieve an overall accuracy between the different output layers that is higher than 94 %. Most importantly, the CSI scores range from 0.72 to 0.86 for both the Sentinel-1 observed flood and water extent products. Due to the highly advanced “ensemble” approach integrating the three robust, cutting edge GFM flood mapping algorithms, and depending on the quality of input data, a flood and water delineation accuracy of > 90% is then expected.