USER REQUIREMENTS
Timeliness
The key element for the GFM is the timeliness of the product generation.
The practical experience of the whole team of the expert flood monitoring alliance has been put at service to guarantee product timeliness less or equal to 8 hours for all Sentinel-1 GRD scenes becoming available on the ESA data hubs within 5 hours.
This paramount requirement is ensured via the following measures:
- a redundant Sentinel data access via multi access point data downloads and parallelization 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.
- the Pre-processing of Sentinel-1 GRD data products and inclusion 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.
- 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 uncertainty values being calculated within a matter of seconds.
- the total lead time of the global flood monitoring product amounts to 60 minutes to complete the entire operational NRT workflow from acquisition to delivery.
. < 8-hour lag between satellite data acquisition and map production
Service availability
Guaranteed service availability is facilitated through EODC’s Sentinel-1 processing operations expertise, begun in 2014, which is regularly being 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 is also organized through redundant 24/7 production coordinator staff availabilities, such that a 99% service availability is guaranteed.
. available 24/7/365 . > 99% service availability . global coverage
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%.
GFM 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, a flood delineation and water mask accuracy of >90% is then guaranteed.
. 90%+ accuracy of flood mapping
