GloFAS skill

Forecast verification is important to understand the strengths and weaknesses of a forecast system and to build confidence in results. It also provides additional information to help decision makers to assess how they can use GloFAS products to make decisions.
The overall GloFAS forecast performance is expressed by a set of skill scores, which highlight different aspects of forecast skill. GloFAS performance is also regularly evaluated for specific events and case studies.

GloFAS provides three skill layers:

• Hydrological Model Performance, which displays modified Kling-Gupta Efficiency (KGE) and its components for stations where daily discharge data are available to GloFAS (the pop-up table clarifies where the station was calibrated in the current operational version). Methodology, data, and results of model calibration are presented in the page of the relevant operational release (one example is GloFAS v4.0 calibration methodology, data, and results; please always verify the latest operational release in the GloFAS versioning page).
• Medium-range Forecast Skill expressed in a maximum lead time (in days), up to 30-days ahead, when the GloFAS river discharge forecast skill (CRPSS; Continuous Ranked Probability Skill Score) is greater than 0.5, evaluated against both persistence and climatology benchmark forecasts with river discharge reanalysis as reference.
• Seasonal Forecast Skill expresses in a maximum lead time (in weeks), up to 16-weeks ahead, when the GloFAS Seasonal river discharge forecast skill (CRPSS; Continuous Ranked Probability Skill Score) is greater than 0.5, evaluated against a weekly climatology benchmark forecast with river discharge reanalysis as reference

A detailed description of the evaluation products made available via the GloFAS Map Viewer is provided by the dedicated GloFAS evaluation products wiki pages (the GloFAS User Guide provides hand-on information on how to explore the Map Viewer).

Users are strongly encouraged to conduct their own analysis to evaluate whether GloFAS forecasts are appropriate for their decision-making. The CEMS-Flood Data User Guide provides information on how to access GloFAS data and products for operational or research use.