The GloFAS hydrological model performance is shown as a clickable layer under the the 'EVALUATION' tab in the GloFAS map viewer. Details on the methodology to compute the verification scores in this layer is provided in GloFAS hydrological model performance.
Hydrological model performance is shown in the GloFAS-IS map viewer for each river gauge where observational data allows us to conduct a observation-based verification. The scores are currently computed over the whole observational period. All stations are included that have observations with high enough quality, with at least 4 years of data over the 1979-2019 reanalysis period. Many of the stations were used in the model calibration exercise, which information is provided in the metadata table on top of the pop-out window (Calibration Yes/No).
The following types of information is provided after clicking on the stations, which are represented by coloured circles according to the KGE score.
Main layer
Pop-up window information
Hydrological model performance metrics
The evaluation metric KGE' and its components are represented in speedometer-like figures.
Monthly discharge climatology
Climatological discharge main statistics (median, interquartile range and outliers) are calculated for each month (displayed over a 14-month period starting in September) for both observed and simulated discharges. The superposition of both shows the (dis)agreement between the two time series, giving a visual confirmation of the KGE and its components.
While the correlation is high if simulation and observation co-vary, the correspondence between the medians and the outliers reflect the bias and variability ratio respectively. The following figure helps to determine systematic errors for specific months or seasons and helps to identify the cause of a potentially low KGE score.
Observation period hydrographs
The daily discharge time series at the model time-step are shown as hydrographs, with observed values highlighted as polygons. The time series plots help to identify particular periods of low model performance, and to understand where a low KGE value might come from. For example, if correlation is fairly good, but the model fails to capture low flows or peak amplitudes correctly, the discharge hydrograph helps to visually identify the quality of the gauged station's observations.
Complete simulation period hydrographs with flood thresholds
The daily simulated time series is plotted in a separate plot for the whole reanalysis period of 1979-2019. In addition, the flood thresholds are also plotted from 2-year to 50-year return period levels, including the three coloured ones (2-, 5- and 20-year) which are specifically used on the hydrographs. In case the time series have very high outlying discharge value, then also 100-year and 200-year could appear on the plot. This 41-year time series indicates how the thresholds relate to the time series, as they are derived from the annual maxima within this time series. Also, this plot can highlight, if there are noticeable trends in the long time series, which can have a significant impact on the representativity of the flood thresholds for the real time forecast period, i.e. leading to flood thresholds that appear too low/high, not representing well the real time period discharge behaviour.
