Latest operational GloFAS release

The following is a description of GloFAS v4.2, available as fully operational GloFAS from 12 November 2024.

For an overview of other GloFAS releases, please see : GloFAS versioning system.

Summary

GloFAS v4.2 introduces several minor changes to the system, including:

• The GloFAS medium-range forecast skill layer has been updated in two key ways:
  • Expanded Reforecast Coverage: In GloFAS v4.0, the forecast skill layer was initially calculated using only the reforecasts for April, May, and June, which were the months available at the time of release. The forecast skill layer in GloFAS v4.2 has now been recalculated using a complete set of reforecasts, covering the entire year. For details see: GloFAS v4 forecast skill.
  • Updated Climatological Benchmark Period: The reference period for the climatological benchmark used to calculate forecast skill has been changed from a 40-year period (1979-2018) to a more recent 20-year period (2003-2022). This update serves several purposes: (1) it provides a more relevant benchmark by using recent data, (2) it aligns the benchmark period with the reforecast period, and (3) it avoids potentially inflating the perceived skill of the forecasts, as a 40-year climatology benchmark may be too easily outperformed. For details see: GloFAS forecast skill
• The GloFAS data dissemination description was updated, including a new catalogue of available data and products for time critical FTP download (FTP).
• Medium-range reforecasts
  • Change in the reforecast dates now released every month on the 1/5/9/13/17/21/25/29 (excluding 29 February) and not every Monday and Thursday as previously done. This may have an implication for users using CEMS-Flood reforecast data in their downstream application as the scheduling of reforecast date will change. See Implementation of IFS Cycle 49r1 for more details.
  • Temporary freeze of medium-range reforecasts available from the EWDS, with no update of the dataset from GloFAS v4.2 release date. If you require access to the reforecast data, please get in touch with us via the ECMWF Support Portal using the title 'Access to GloFAS Reforecast Data' when creating the ticket. Information on how to raise a ticket in our support portal is available here.

This upgrade of GloFAS has no impacts on the GloFAS modelling results.

Technical details