USER REQUIREMENTS
Timeliness
A key element for the GFMS is the timeliness of the product generation.
The practical experience of the whole team of the expert flood monitoring alliance adequate measures to ensure a guaranteed product timeliness less or equal to 8 hours for all Sentinel-1 GRD scenes becoming available on the ESA data hubs within 5 hours.
In summary, product timeliness of less than 8 hours will be ensured via the following measures:
- a redundant Sentinel data access via multi access point data downloads and parallelisation of downloads for an optimised bandwidth utilisation via the HubWatcher software.
- the automatic retrieval of Sentinel-1 GRD data with the HubWatcher in 96.3 minutes on average following ESA publication for general availability. There is already understanding of the requisite steps to be taken to further decrease this value to provide available within 60 minutes.
- the Pre-processing of Sentinel-1 GRD data products and insertion into the data cube format within 10-20 minutes per scene.
- the fast data access to the data cube with IO speeds of 15GiB/s or 120Gbps. This will further increase with the proposed high-speed replicated storage.
- the generation of the ensemble global flood monitoring product using the three parallel algorithms consumes up to 30 minutes, with the final flood extent maps and uncertainly values being calculated within a matter of seconds.
- the total lead time of the global flood monitoring product can be given with 60 minutes to complete the entire operational NRT workflow from acquisition to delivery.
Service availability
Guaranteed service availability is facilitated through EODC’s 6 year old Sentinel-1 processing operations expertise, which is regularly being assessed by the ESA mission reports, and which lessons learned will be used to implement a completely independent IT infrastructure for the CEMS GFM system operations. The operations will be also organized through redundant 24/7 production coordinator staff availabilities, such that we can guarantee a 99% service availability
Product accuracy
According to the general product specifications, the thematic accuracy of the Sentinel-1 observed flood and water extent products is required to exceed a target CSI score of 70-80 %. GFMS on multiple testcases has proven to achieve an overall accuracy between the different products 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 methods and quality of input data we can guarantee a flood delineation and water mask accuracy of >90%, significantly excelling the minimum requirements.
