The CEMS-flood sub-seasonal and seasonal products are essentially the same across the two systems and similarly the same across EFAS and GloFAS. Below we introduce the available products.
River network summary map
The river network summary map layer shows the combined forecast anomaly and uncertainty signal in a simplified way for each forecast lead time (Figure 1a). The lead time is weekly (always Monday to Sunday, with the weekly average river discharge) in the sub-seasonal and monthly (always calendar month, with the monthly average river discharge).
The forecasts can be advanced (or even animated if needed) with the lead time controller (see Figure 1a) and the users can check the individual signal for each lead time, which currently is 5 or 6 weeks for the sub-seasonal (depending on which day of the week the run date is) and always 7 months for the seasonal.
The forecast signal is shown by colouring for all river pixels above a certain minimum catchment area (currently 50 km2 in EFAS and 250 km2 in GloFAS). Each of these river pixels are coloured by the dominant anomaly category and the also by the uncertainty category.
There are 7 anomaly categories and three uncertainty categories defined, based on the extremity level of the ensemble forecast members in the 99-value percentile climatological distribution. The details of the computation methodology is described here: Placeholder CEMS-flood sub-seasonal and seasonal forecast anomaly and uncertainty computation methodology.
On the river network summary map only 5 anomaly categories are displayed after combining the middle three into one larger 'Near normal' category, which allow the users to focus visually on the larger anomalies. Each of these categories are divided into three sub-categories by the uncertainty, as low, middle and high uncertainty, in total making it into 15 forecast signal categories. Figure 1b shows the assigned colours and the corresponding extremity levels (or climatological percentiles groups). Each of the 5 anomaly categories have a distinct colour, where the three uncertainty levels is indicated by lighter colours as the uncertainty increases.
The river network summary map also contains the reporting points (see Figure 1a). These are river locations, where detailed information is provided about the evolution of the forecast signal over the forecast horizon. There reporting points are either fixed points, which are also used in the medium-range flood products and the basin-representative points, which are selected locations, on a one point per basin basis. Further details about the basins and the representative points are available here: Placeholder CEMS-flood sub-seasonal and seasonal basins and representative stations.
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Example snapshots of the sub-seasonal and seasonal river network summary maps with the reporting points, animation and colours explained.
Reporting point pop-up window
At the predefined reporting point locations (either fixed or basin-representative), further detailed information is provided about the evolution of the forecast signal.
The first table provides metadata information of the station, name (if available), country, river, provided coordinates and upstream area and also LISFLOOD coordinates and upstream area. The provided coordinates and upstream area are from the users as represent the real rivers with the real location. These are available only for the fixed points (sometimes provided upstream area is missing). For the basin-representative points, only the LISFLOOD coordinates and upstream area are available, as these points were dedicatedly defined on the simulated LISFLOOD river network only.
Next is the hydrograph, which graphically summarises the climatological, antecedent and forecast conditions.
Figure 2. Example snapshot of the reporting point pop-up window product (for a seasonal forecast).