Implemented by the European Commission as part of the Copernicus Programme
The Global Flood Awareness System (GloFAS) is one component of the Copernicus Emergency Management Service
(CEMS). It is designed to support preparatory measures for flood events worldwide, particularly in large
transnational river basins.
To provide information on both upcoming and ongoing flood events, GloFAS combines information from
satellites, models and in-situ measurements to produce:
GloFAS forecasts are produced using the latest ensemble of Numerical Weather Prediction (NWP) forecasts of
the ECMWF Integrated Forecast System (IFS). The medium- and extended-range ensemble outputs are used for
GloFAS forecasts, and the long-range SEAS5 ensemble is used for GloFAS Seasonal forecast.
ECMWF-ENS
is the ensemble forecast of ECMWF and consists of 51 members at ~9 km resolution up to 15 days, increasing
to 36 km from day 16 to 30. In GloFAS 30-day, the outputs of the 00:00 UTC IFS medium-range runs are used
daily for day 1 to 15, and the latest available IFS extended range runs used for day 16 to 30.
SEAS5 is the ensemble seasonal forecast of ECMWF (operational since 5 November 2017), and one of the
seasonal forecast models of the Copernicus Climate Change Service. It consists of 51 members at ~36 km
horizontal resolution. Based on SEAS5, GloFAS Seasonal forecasts provide hydrological outlooks which show
the likelihood of high or low flows within the coming sixteen weeks in a region and the GloFAS river network
once a month.
A more detailed description of GloFAS meteorological forecasts is available from
this
page of the
CEMS-Flood Wiki.
A hydrological model transforms the meteorological forcing forecasts into hydrological forecasts by
mimicking the hydrological land processes by a set of equations. The hydrological model Open Source LISFLOOD
has been used to generate GloFAS medium- and seasonal-range forecasts starting from GloFAS v3.1 (May
2021).
Open Source LISFLOOD (OS LISFLOOD) is a spatially distributed, physically based hydrological
model which has been developed by the Joint Research Centre (JRC) of the European Commission since 1997 (
De Roo et al., 2000).
The numerical simulation is driven by meteorological forcing data (precipitation, temperature, and potential
evapo-transpiration): the model solves the water balance at every time step and for each grid cell. A set of
raster maps showing terrain morphology, soil properties, land cover and land use features, and water demand,
enables the modelling of the hydrological cycle in different climates and socio-economic contexts. The OS
LISFLOOD source code, model documentation, user guide, and ancillary tools (including calibration scripts)
can be accessed via the OS LISFLOOD page.
GloFAS OS LISFLOOD implementation uses daily time steps; model spatial resolution was 0.1°
up to GloFAS
v3.5, it was increased to 0.05° (approximately 5 km at the Equator) with GloFAS v4.0 (July
2023).
Information about OS LISFLOOD raster maps is available from the following page:
land
surface
implementation maps. Technical description of each operational release can be accessed from
CEMS GloFAS
versioning
system, with this page
providing information on the latest operational release.
Finally, an overview of the hydrological models used within the past GloFAS operational releases is
available from this page