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The following is a description of the latest operational release of EFAS v4.6. For EFAS v4.7. For an overview of other EFAS releases, please see: EFAS versioning system

Summary

EFAS v4.6 introduces minor changes to the system, as well as some general bug fixes7 enables the visualisation of the new Global Flood Monitoring (GFM) products in the CEMS EFAS map viewer. The GFM provides continuous monitoring of floods worldwide, by automatically processing and analysing in near real-time all incoming Synthetic Aperture Radar imagery acquired by the EU’s Copernicus Sentinel-1 satellites. Here is a summary of the main changes: 

1. New version of LISFLOOD

LISFLOOD version 3.2.0 is used in this EFAS release. It includes important developments, such as:

• enhanced code capability to handle inputs;
• new netCDF readers based on xarray that allow for more flexibility and efficiency, dramatically decreasing the time required to load large inputs thus leading to improved computational performances;
• extensive use of unit tests to verify the functioning of the model and enhance collaborative development of the code;
• improvements of the management of latitude and longitude grids to allow maximum precision of the reference system;
• porting of the code to python3.

The modelling of the hydrological processes has not changed compared to the version of the model used in the previous EFAS release.

For more information, please visit the dedicated GitHub space: https://github.com/ec-jrc/lisflood-code/releases

2. Rapid Risk Assessment layers

• The code used to generate the rapid risk assessment layers has been rewritten using python 3 and was integrated to the general product generation framework.
• In the Rapid Impact Assessment layer, the information which appears in the pop out window when a shaded region is clicked has been reformatted:
  • Exposure information appears within a first table which summarises the population, road network and landcover potentially affected.
  • A second table summarises the flood event information, including the start and of the flooding based on the forecast median and mean exceedance probabilities for different return period thresholds.
• In the Rapid Flood Mapping layer, the inundation extent now corresponds to the unprotected scenario which does not consider the role of flood defences. Previously the layer showed the inundation extent when considering the role of flood defences.

3. COSMO-LEPS

• The EFAS suite has been modified to automatically detect an outage of the provision of the COSMO-LEPS forecasts
• In this situation the reporting points product and associated products will proceed without the COSMO-LEPS forecasts
• The ERIC flash flood forecasts will not be produced as they rely solely upon the provision of the COSMO-LEPS forecasts

The GFM product is based on 3 different flood detection algorithms running in parallel and is composed by 11 different layers, roughly grouped into 4 categories: water bodies (Observed Flood Extent, Observed Water Extent, Reference Water Mask), uncertainty-related (Exclusion mask, Uncertainty values, Advisory flags), S1 data specifics (metadata, footprint, schedule) and impacts estimate (Affected population, Affected land cover).

With a spatial resolution of 20m and a revisit time ranging from 3 to 14 days depending on S-1 overpasses, the full dataset of the product output layers is made available in raster format both separately and in bulk.

The information about the specifics of the GFM products and how to access the data are provided through the GFM Product User Manual and the Product Description Document available here

Technical details