Example of the 6-hourly water balance and ECMWF-ENS driven medium range forecasts available through EFAS v4.0
Example of the 6-hourly water balance and ECMWF-ENS driven medium range forecasts available through EFAS v4.0

EFAS version 4.0 was launched on 14 October 2020. It introduces a step-change with the medium-range ensemble forecasts driven by ECMWF-ENS now provided at a 6-hourly time step.

EFAS 4.0 follows a complete recalibration at 6-hourly time step of EFAS hydrological model, LISFLOOD, now based on over 1100 river stations across the EFAS domain covering about 50% of the full spatial domain. The newly calibrated LISFLOOD results in a marked improvement in both the magnitude and timing of the simulated flood peaks, especially in medium-size catchments (see Figure 1 for an example of improved hydrographs with EFAS v4.0).

 

EFAS 3.6 and 4.0 hydrograph comparison
Figure 1: Hydrographs of the water balance layer provided by EFAS v3.6 (left) and EFAS v4.0 (right) for the Inn at Muehldorf, Germany (12600km2) produced on 11 August 2020 : discharge observations (black), simulations forced with observed precipitation and air temperature (green) and with forcings from the fill-up period (red), and medium-range ECMWF-ENS ensemble forecasts (blue). (Information restricted to EFAS partners only).

For more information on EFAS we refer to the dedicated Wiki pages publicly available at: https://confluence.ecmwf.int/display/COPSRV/European+Flood+Awareness+System.

A new medium- to sub-seasonal range reforecast, seasonal forecast and seasonal hindcast datasets have also been released with EFAS v4.0. Seasonal and seasonal reforecasts datasets will be available from ~10 November 2020 following the first seasonal forecast in EFAS v4.0. The reforecasts are available through the CDS: https://doi.org/10.24381/cds.c83f560f