The following is a description of GloFAS v4.0, which is available as pre-release on the GloFAS Stage Platform from 05 July 2023. The full operational GloFAS v4.0 will be released soon.

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

Summary

GloFAS v4.0 introduces a number of major changes to the system, including:

• higher spatial resolution. GloFAS v4.0 has 0.05 degrees resolution (~5km), as opposed to all the previous GloFAS versions having 0.1 degrees resolution (~10km).
• an entirely new set of 0.05 degrees resolution input maps produced using the most recent research findings, remote sensing, and in-situ datasets.
• major improvements to the open-source hydrological model LISFLOOD.
• a new hydrological model calibration at 1996 in-situ gauging stations. Furthermore, a parameter regionalisation was performed to estimate the parameters of catchments for which in situ discharge observations were not available.
• new return period thresholds and snow water/soil moisture anomaly maps based on a climatology from 1980 – 2022. The GloFAS v4.0 river discharge climatology is available at the C3S Climate Data Store.
• updated GloFAS Seasonal forecasts using the newly calibrated, higher resolution hydrological model.

This major version change is associated with an update of the historical hydrological reanalysis. 

This upgrade of GloFAS has large impacts on the GloFAS modelling results.

31 stations were also added to the reporting point: 9 stations in Canada, 7 stations in Russia, 4 stations in Finland, 3 stations in Argentina and 1 station in each of Brazil, United States, Morocco, Benin, Uganda, Thailand, Columbia and South Africa.

Technical details