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Summary

The following is a description of the latest operational release of EFAS v4 v5.81. For an overview of other EFAS releases, please see: EFAS versioning system. 

Summary

EFAS v4.8 integrates changes in its meteorological forcing with the use of the new version of the ECMWF-ENS ensemble forecasting system, introduced by IFS cycle 48r1. This change in the forcing data has the following impacts on EFAS:

• Hydrological monitoring:
  • No change in the observation-forced hydrological reanalysis simulations and the ECMWF-HRES-forced forecast initialisation (the so-called fill-up, where observations not yet available).
• Real time forecasts:
  • The spatial resolution of the forcing increases from 18 km to 9 km for the medium-range EFAS forecasts.
  • The sub-seasonal EFAS forecasts are now produced every day, instead of only twice a week for Mondays and Thursdays. The meteorological forcing comes from the new extended range forecasts in 48r1, produced every day for the 00 UTC cycle, on the same 36 km spatial resolution as before.
• Reforecasts:
  
  • EFAS v4.8 will not have a new 48r1-specific hydrological reforecast data set.
• Seasonal forecasts and seasonal reforecasts:
  • There is no impact on the seasonal hydrological modelling system.

More details on the 48r1 meteorological modelling changes can be found on the Implementation of IFS Cycle 48r1 page.

Technical details

v5.1 introduces several minor changes to the system, including:

• A new "Release News" pop-up that shows up on EFAS-IS when a new version of EFAS (minor and major) is released, including information on the release highlights and a link to the wiki for further information.
• Notification Feedback improvements, allowing EFAS partners to edit feedback they have submitted previously, allowing to specify the region for which the feedback was given (if the notification spans multiple), and a system for automatic notification reminders that will be rolled out shortly after the release day. See 4.4 How to provide feedback for details. 
• Updates to EFAS Hydrological post-processing
  • new calibration of all viable stations including 270 new stations (250 stations at 6-hourly and 20 stations at daily). Results are in EFAS v5.1 - Hydrological Post-Processing Calibration Evaluation page.
  • updates to post-processed hydrographs based on feedback from the 18th EFAS Annual Meeting. See EFAS Reporting Points for an example.
• Increased offering of monitoring and forecast variables for EFAS made available through the Climate Data Store. See Model Output page for details.
  • Runoff Water Equivalent (surface plus subsurface)
  • Soil Wetness Index (root zone)
  • Withdrawal of 'Volumetric Soil Moisture Content' variable from CDS (from EFAS v5.1 release onwards, 2024-03-20).

The data is available for the reanalysis (from 1992-01-01 to near real-time), the medium range forecasts (from EFAS v5.1 onwards), and the seasonal forecasts (from April 2024).The soil wetness index (root zone) and runoff water equivalent (surface plus subsurface) variables added with EFAS v5.1 on 2024-03-21 will only be available 30 days after the forecast date.

• EFAS flood thresholds
  • EFAS flood threshold made available on wiki at Auxiliary Data page.
  • Bug fixes to flood threshold calculation 
• New stations added to Reporting Points layer on EFAS-IS. EFAS-IS is now showing 3617 fixed reporting points (river gauges) for which the model drainage area is larger than 50 km2. This is an increase of 278 fixed reporting points compared to previous EFAS version. 
• Revised ERIC Reporting Points
  • The minimum upstream area for plotting a reporting point has been increased to 150 km² (up from 50 km² previously). This reduces the number of reporting points that are plotted.

• Retirement of ERICHA products

  • ERICHA Flash Flood products will be phased out in favour of the improved TAMIR products which include radar-nwp blended precipitation, ensemble-based hourly forecasts and flood impact products. More details can be found in TAMIR flash flood nowcasting wiki page.

This upgrade of EFAS has no impact on the EFAS modelling results.

Technical details