This page page describes the model output data (either direct output or processed) available from EFAS and GloFAS. Please see see Data Access to obtain the data and Working with CEMS-Flood Data for examples of how to open, extract subsets and visualise the data.
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EFAS Available Data
Presented here is a brief overview of the EFAS data made available to the public and registered EFAS users. For a full overview of the EFAS hydrological model LISFLOOD, please go to the dedicated pages. You will find information on the latest release of EFAS here: Latest operational EFAS release
EFAS datasets
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EFAS HistoricalThis dataset provides gridded modelled hydrological time series forced with meteorological observations. The data set is a consistent representation of the most important hydrological variables across EFAS. The temporal resolution is up to 30 years modelled time series of:
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It also provides static data on soil depth for the three soil layers. |
Volumetric oil moisture and river discharge data are accompanied |
by Auxiliary Data for interpretation. This dataset was produced by forcing the LISFLOOD hydrological model with gridded observational data of precipitation and temperature at a |
1x1 arcminute (for version 5.0 onwards) resolution across the EFAS domain. The most recent version uses a 6-hourly time step, whereas older versions uses a 24-hour time step. It is available from |
1992-01-01 up until near-real time, with a delay of 6 days. The real-time data is only available to EFAS partners. Data can be accessed is several ways, the most common is through the CDS (see Data Access). |
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EFAS Real-time ForecastsThis |
EFAS real-time forecasts
Thisdataset provides gridded modelled hydrological time series forced with medium-range meteorological forecasts from EFAS. The temporal resolution is sub-daily high-resolution and ensemble forecasts of:
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It also provides static data on soil depth for the three soil layers. |
Volumetric soil moisture and river discharge data are accompanied by Auxiliary Data for interpretation. This data set was produced by forcing the LISFLOOD hydrological model at a |
1x1 arcminute (for version 5.0 onwards) resolution with meteorological forecasts. The forecasts are initialised twice daily at 00 and 12 UTC with time steps of 6 or 24 hours and lead times between 5 and 15 days depending on the forcing numerical weather prediction model. The forcing EFAS Meteorological forecasts are high-resolution and ensemble forecasts from ECMWF with 51 ensemble members, high-resolution forecasts from the Deutsches Wetter Dienst (DWD) and the ensemble forecasts from the COSMO Local Ensemble Prediction System (COSMO-LEPS) with 20 ensemble members. The hydrological forecasts are available from 2018-10-10 up until present with a 30-day delay. The real-time data is only available to EFAS partners. Data can be accessed is several ways, the most common is through the CDS (see Data Access). |
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DATA DESCRIPTION
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EFAS Reforecasts |
This dataset provides gridded modelled hydrological time series forced with medium- to sub-seasonal range meteorological reforecasts from EFAS. The temporal resolution is 20 years of sub-daily reforecasts initialised twice weekly (Mondays and Thursdays) of:
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It also provides static data on soil depth for |
the three soil layers. |
Volumetric soil moisture and river discharge data are accompanied by Auxiliary Data for interpretation. This dataset was produced by forcing the LISFLOOD hydrological model at a |
1x1 arcminute (for version 5.0 onwards) resolution with ensemble meteorological reforecasts from ECMWF. Reforecasts are forecasts run over past dates and are typically used to assess the skill of a forecast system or to develop tools for statistical error correction of the forecasts. The reforecasts are initialised twice weekly with lead times up to 46 days, at 6-hourly time steps for 20 years. For more specific information on the how the reforecast dataset is produced we refer to EFAS medium-range forecast skill. Data can be accessed is several ways, the most common is through the CDS (see Data Access). |
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EFAS Seasonal real-time forecastsThis dataset provides gridded modelled daily hydrological time series forced with seasonal meteorological forecasts from EFAS. The temporal resolution is daily forecasts initialised once a month consisting of:
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It also provides static data on soil depth for the three soil layers. |
Volumetric soil moisture and river discharge data are accompanied by Auxiliary Data for interpretation. This dataset was produced by forcing the LISFLOOD hydrological model at a |
1x1 arcminute (for version 5.0 onwards) resolution with seasonal meteorological ensemble forecasts. The forecasts are initialised on the first of each month with a lead time of 215 days at 24-hour time steps. The meteorological data are seasonal forecasts (SEAS5) from ECMWF with 51 ensemble members. The forecasts are available from November 2020. Data can be accessed is several ways, the most common is through the CDS (see Data Access). |
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EFAS Seasonal reforecastsThis dataset provides modelled daily hydrological time series forced with seasonal meteorological reforecasts from EFAS. The temporal resolution is daily forecasts initialised once a month over the reforecast period 1991-2020 of:
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It also provides static data on soil depth for the three soil layers. Volumetric soil |
moisture and river discharge data are accompanied by Auxiliary Data for interpretation. This dataset was produced by forcing the LISFLOOD hydrological model at a |
1x1 arcminute (for version 5.0 onwards) gridded resolution with seasonal meteorological ensemble reforecasts. Reforecasts are forecasts run over past dates and are typically used to assess the skill of a forecast system or to develop tools for statistical error correction of the forecasts. The reforecasts are initialised on the first of each month with a lead time of 215 days at 24-hour time steps. The forcing meteorological data are seasonal reforecasts from ECMWF, consisting of 25 ensemble members up until December 2016, and after that 51 members. Hydrometeorological reforecasts are available from 1991-01-01 up until 2020-10-01. Data can be accessed is several ways, the most common is through the CDS (see Data Access). |
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EFAS variables
EFAS variables (called 'parameters' in ECMWF MARS
EFAS variables
EFAS variables (called 'parameters' in ECMWF MARS) are the hydrological entities calculated by the modelling chain.
Three types of EFAS From EFAS v5.1, the following variables are made available: river discharge, snow depth water equivalent and volumetric soil moisture content. A short description is given below in the below table along with associated metadata information .
Table: Available EFAS variables
- River discharge,
- Soil wetness index (root zone) (see Soil wetness index (root zone) for details),
- Runoff water equivalent (surface plus subsurface),
- Snow depth water equivalent.
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For EFAS v5.0 and earlier, the variable 'volumetric soil moisture content' was available. This variable has been withdrawn since the release of EFAS v5.1 on 2024-03-20. For EFAS v3.5 and earlier, all variables were only available for 24-hourly time steps. Since EFAS v4.0, all variables are only available for 6-hourly time steps (but can be aggregated to 24-hourly for all non-instantaneous variables). |
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Short Description | Unit | GRIB parameter ID | GRIB Short name | GRIB Name | Comment | GRIB description | CDS description |
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| River discharge | m3/s | 240023/ 240024 | dis06/ dis24 | Mean discharge in the last 6/ 24 hours | Average | Volume rate of water flow, including sediments, chemical and biological material, in the river channel averaged over a time step through a cross-section | Same as GRIB description |
| Snow depth water equivalent | kg/m2 (mm) | 228141 | sd | Snow depth water equivalent | Instantaneous at the end of the model time step | Snow depth water equivalent in kg m**-2 (mm) water equivalent | The value represents the mass of water per square meter if all the snow in the grid box would be melted. The value is instantaneous meaning that it is valid for the last time step of the integration at the issued model time step |
m3 /m3
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| Soil wetness index (see Soil wetness index (root zone) for details) | Numeric | 231026 | swir | Soil wetness index (root zone) | Instantaneous at the end of the model time step |
Available for three soil layers
Volumetric soil moisture
Soil depth
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EFAS variable river discharge (dis) is stored as average over the time step of the model (6-hourly or 24-hourly), with time stamp (date and time of end of averaging period) explicit in the GRIB short name. In EFAS, river discharge is calculated in each grid box of the hydrological model. However, not all grid boxes correspond to a river segment, and because of the relatively coarse resolution of the EFAS gridded domain, the modelled river network in EFAS might be associated with slightly different latitude-longitude than in the real world. It is hence essential that when extracting river discharge data, the user also checks the upstream area of the grid box of interest. The EFAS upstream area can be found in the Auxiliary Data pages. Some short scripts to use as examples are provided in the Working with CEMS-Flood Data pages. |
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Snow depth water equivalent represents the amount of water stored as ice and snow given as an instantaneous value at the end of each model time step. The time stamp (date and time of end of time step period) is explicit in the GRIB short name. In EFAS, snow depth water equivalent in each grid box is calculated from three elevation-related bands to account for the difference in the melting rate with snow condition (see Auxiliary Data for more details). However, only the more directly usable composite snow map representing the total snow water equivalent for each grid box is made available. Some short scripts to use as examples are provided in the Working with CEMS-Flood Data pages. |
| The volume of water over the total volume of voids in the soil, expressed as an index with values between 0 (residual soil moisture) and 1 (saturation), representing the lower and upper soil moisture limits of the root zone. The root zone is the maximum depth at which plants can extract water from the soil. Voids are empty spaces in the soil column that can be filled with water or air. | The volume of water over the total volume of voids in the soil, expressed as an index with values between 0 (residual soil moisture) and 1 (saturation), representing the lower and upper soil moisture limits of the root zone. The root zone is the maximum depth at which plants can extract water from the soil. Voids are empty spaces in the soil column that can be filled with water or air. | ||||||
| Runoff water equivalent | kg/m2 | 231002 | rowe | Runoff water equivalent (surface plus subsurface) | Accumulation | Some water from rainfall, melting snow, or deep in the soil, stays stored in the soil. Otherwise, the water drains away, either over the surface (surface runoff), or under the ground (sub-surface runoff) and the sum of these two is simply called 'runoff'. This parameter is the total amount of water accumulated over a particular time period which depends on the data extracted.The units of runoff are depth in metres. This is the depth the water would have if it were spread evenly over the grid box. Care should be taken when comparing model parameters with observations, because observations are often local to a particular point rather than averaged over a grid square area. Observations are also often taken in different units, such as mm/day, rather than the accumulated metres produced here. Runoff is a measure of the availability of water in the soil, and can, for example, be used as an indicator of drought or flood. | The sum of the surface and sub-surface runoff, and represents all the water that would drain away from the grid box. This variable is the total amount of water accumulated from the beginning of the time step to the end of the time step. |
Soil depth | m | 260367 | sod | Soil depth | Set of three values. Depth from the surface to the bottom of each layer | Soil depth, positive downward. It is meant to be used together with the type of level 'soil level' to encode the depth of the level at each grid point | Soil depth, positive downward for each of the three soil layers at each grid point. The value is relative from the top of the land surface to the bottom of each layer respectively |
Volumetric soil moisture content (Withdrawn on 2024-03-20) | m3 /m3 | 260199 | vsw | Volumetric soil moisture | Instantaneous at the end of the model time step Available for three soil layers | Volumetric soil moisture | Amount of water in a cubic meter of soil valid for the cell grid at the corresponding soil layer. The value is instantaneous meaning that it is valid for the last time step of the integration at the issued model time step. For more documentation on the calculation of the volumetric soil moisture we refer to the documentation. |
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EFAS variable river discharge (dis) is stored as average over the time step of the model (6-hourly or 24-hourly), with time stamp (date and time of end of averaging period) explicit in the GRIB short name. In EFAS, river discharge is calculated in each grid box of the hydrological model. However, not all grid boxes correspond to a river segment, and because of the relatively coarse resolution of the EFAS gridded domain, the modelled river network in EFAS might be associated with slightly different latitude-longitude than in the real world. It is hence essential that when extracting river discharge data, the user also checks the upstream area of the grid box of interest. The EFAS upstream area can be found in the Auxiliary Data pages | ||||||
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Soil moisture content represents the amount of water stored in the soil layers given as an instantaneous value at the end of each model time step. The time stamp (date and time of end of time step period) is explicit in the GRIB short name. EFAS soil moisture content in each grid box is calculated in three layers, top, intermediate and bottom, each associated with a given soil depth (depth from top to bottom of that layer). Information for each 3 layers is provided as separate data field, the soil depth (see Auxiliary Data for more details). EFAS soil moisture information is stored as volumetric soil moisture content for each layer. The associated volume of water for that layer is volumetric soil moisture content multiplied by the layer thickness. The thickness of a specific layer is the difference between the depth of two consecutive layers. The total volume soil moisture content is the sum of volume of water for each layer. Note that in EFAS-IS, only soil moisture of the first 2 layers is shown. Some short scripts to use as examples are provided in the Working with CEMS-Flood Data pages. |
EFAS Horizontal Resolution and projection
The LISFLOOD operational model is setup over Europe with the spatial resolution of 5 * 5 km with the geographical projection is the INSPIRE compliant ETRS89 Lambert Azimuthal Equal Area Coordinate Reference System (ETRS-LAEA). ETRS-LAEA is a single projected coordinate reference system for the pan-European area. It is based on the ETRS89 geodetic datum and the GRS80 ellipsoid, and is the recommended projection for pan-European statistical mapping at all scales or for other purposes where true area representation is required. Its defining parameters can be found here.
Proj4 format: Proj4js.defs["EPSG:3035"] = " +proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 +ellps=GRS80 +units=m +no_defs "
GloFAS Available Data
Presented here is a brief overview of the GloFAS data made available to the public. For a full overview of the GloFAS system, please go to the dedicated wiki pages. You will find information on the latest releases here: Latest operational GloFAS release
GloFAS datasets
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Snow depth water equivalent represents the amount of water stored as ice and snow given as an instantaneous value at the end of each model time step. The time stamp (date and time of end of time step period) is explicit in the GRIB short name. In EFAS, snow depth water equivalent in each grid box is calculated from three elevation-related bands to account for the difference in the melting rate with snow condition (see Auxiliary Data for more details). However, only the more directly usable composite snow map representing the total snow water equivalent for each grid box is made available. Some short scripts to use as examples are provided in the Working with CEMS-Flood Data pages. |
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Soil wetness index (root zone) represents the volume of water stored in the soil layers given as an instantaneous value at the end of each model time step. EFAS soil wetness information is stored as the fraction of the total volume of voids in the root zone. The root zone is the maximum depth at which plants can extract water from the soil. Voids are empty spaces in the soil column that can be filled with water or air. See Soil wetness index (root zone) for details. |
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Runoff water equivalent (surface and subsurface) represents the sum of the surface and sub-surface runoff, and represents all the water that would drain away from the grid box. This variable is the total amount of water accumulated from the beginning of the time step to the end of the time step. NOTE: If this variable were to be expressed as a value over the time step (e.g. 'runoff over the last 24 hours), it would become an average flux. |
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Volumetric soil moisture content represents the amount of water stored in the soil layers given as an instantaneous value at the end of each model time step. The time stamp (date and time of end of time step period) is explicit in the GRIB short name. EFAS volumetric soil moisture content in each grid box is calculated in three layers, top, intermediate and bottom, each associated with a given soil depth (depth from top to bottom of that layer). Information for each 3 layers is provided as separate data field, the soil depth (see Auxiliary Data for more details). EFAS volumetric soil moisture information is stored as volumetric soil moisture content for each layer. The associated volume of water for that layer is volumetric soil moisture content multiplied by the layer thickness. The thickness of a specific layer is the difference between the depth of two consecutive layers. The total volume soil moisture content is the sum of volume of water for each layer. Note that in EFAS-IS, only soil moisture of the first 2 layers is shown. Some short scripts to use as examples are provided in the Working with CEMS-Flood Data pages. |
EFAS Horizontal Resolution and Projection
Since EFAS v5.0, the LISFLOOD operational model is setup over Europe with the spatial resolution of 1 arcmin/ 0.0166667 degrees resolution (~1.4km). The geographical projection is the World Geodetic System 1984 (EPSG 4326). Its defining parameters can be found here.
Proj4 format: Proj4js.defs["EPSG:4326"] = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"
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For EFAS v4.0 and earlier, the LISFLOOD operational model was setup over Europe with the spatial resolution of 5 * 5 km with the geographical projection is the INSPIRE compliant ETRS89 Lambert Azimuthal Equal Area Coordinate Reference System (ETRS-LAEA). ETRS-LAEA is a single projected coordinate reference system for the pan-European area. It is based on the ETRS89 geodetic datum and the GRS80 ellipsoid, and is the recommended projection for pan-European statistical mapping at all scales or for other purposes where true area representation is required. Its defining parameters can be found here. Proj4 format: Proj4js.defs["EPSG:3035"] = " +proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 +ellps=GRS80 +units=m +no_defs " |
Recommendation regarding EFAS outputs
We do not recommend to use EFAS for catchments below 50 km2, most of our products/layers use 150 km2 as a threshold (i.e. we do not evaluate the model skill/performance in catchments smaller than 150 km2).
GloFAS Available Data
Presented here is a brief overview of the GloFAS data made available to the public. For a full overview of the GloFAS system, please go to the dedicated wiki pages. You will find information on the latest releases here: Latest operational GloFAS release
GloFAS datasets
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GloFAS HistoricalThis dataset contains global modelled daily data of river discharge from GloFAS. River discharge. This dataset is simulated by forcing the the LISFLOOD hydrological modelling chain with inputs from the ERA5 global reanalysis. Data availability for the operational historical simulation is from 1979-01-01 up to near real time. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
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GloFAS historical
This dataset contains global modelled daily data of river discharge from GloFAS. River discharge. This dataset is simulated by forcing the the LISFLOOD hydrological modelling chain with inputs from the ERA5 global reanalysis. Data availability for the historical simulation is from 1979-01-01 up to near real time. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
Table: River discharge and related historical data from GloFAS
GloFAS real-time forecasts
This dataset contains global modelled daily data of river discharge forced with meteorological forecasts from GloFAS. This dataset is simulated by forcing the the LISFLOOD hydrological modelling chain with input from ECMWF ensemble forecast combined with the ECMWF extended-range ensemble forecast up to 30 days. Data availability for the GloFAS forecast is from 2019-11-05 up to near real time. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
Table: River discharge and related forecasted data from GloFAS
GloFAS reforecasts
This dataset provides a gridded modelled time series of river discharge, forced with medium- to sub-seasonal range meteorological reforecasts from GloFAS. This dataset was produced by forcing the LISFLOOD hydrological modelling chain with input from the ECMWF-ENS 11-member ensemble reforecasts. Reforecasts are forecasts run over past dates, and those presented here are used for providing a suitably long time period against which the skill of the 30-day real-time operational forecast can be assessed. The reforecasts are initialised twice weekly with lead times up to 46 days, at 24-hour steps for 20 years in the recent history. For more specific information on the how the reforecast dataset is produced we refer to GloFAS forecast skill. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
Table: Reforecasts of river discharge and related data from GloFAS
GloFAS Seasonal real-time forecasts
This dataset provides a gridded modelled time series of river discharge, forced with seasonal range meteorological forecasts from GloFAS. This dataset was produced by forcing the LISFLOOD hydrological model at a 0.1° (~11 km at the equator) resolution with downscaled runoff forecasts from the ECMWF 51-member ensemble seasonal forecasting system, SEAS5. The forecasts are initialised on the first of each month with a 24-hourly time step, and cover 123 days. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
Table: Seasonal river discharge forecasts andSeasonal forecasts of river discharge and related data from GloFAS
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GloFAS Seasonal reforecasts
This dataset provides a gridded modelled time series of river discharge forced with seasonal range meteorological reforecasts from GloFAS. This dataset was produced by forcing the LISFLOOD hydrological modelling chain with input from the ECMWF ensemble seasonal forecasting system, SEAS5. For the period of 1981 to 2016 the number of ensemble members is 25, whilst reforecasts produced for 2017 onwards use a 51-member ensemble. Reforecasts are forecasts run over past dates, with those presented here used for producing the seasonal river discharge thresholds. In addition, they provide a suitably long time period against which the skill of the seasonal forecast can be assessed. The reforecasts are initialised monthly and run for 123 days, with a 24-hourly time step. For more specific information on the how the seasonal reforecast dataset is produced we refer to the documentation. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
Table: Seasonal reforecasts of river discharge and related data from GloFAS
GloFAS variables
GloFAS variables (called 'parameters' in ECMWF MARS) are the hydrological entities calculated by the modelling chain. For GloFAS only river discharge is made available. A short description is given below in the below table along with associated metadata information.
Table: Available GloFAS variables
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GloFAS real-time forecastsThis dataset contains global modelled daily data of river discharge forced with meteorological forecasts from GloFAS. This dataset is simulated by forcing the the LISFLOOD hydrological modelling chain with input from ECMWF ensemble forecast combined with the ECMWF extended-range ensemble forecast up to 30 days. Data availability for the GloFAS forecast is from 2019-11-05 up to near real time. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
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GloFAS reforecastsThis dataset provides a gridded modelled time series of river discharge, forced with medium- to sub-seasonal range meteorological reforecasts from GloFAS. This dataset was produced by forcing the LISFLOOD hydrological modelling chain with input from the ECMWF-ENS 11-member ensemble reforecasts. Reforecasts are forecasts run over past dates, and those presented here are used for providing a suitably long time period against which the skill of the 30-day real-time operational forecast can be assessed. The reforecasts are initialised twice weekly with lead times up to 46 days, at 24-hour steps for 20 years in the recent history. For more specific information on the how the reforecast dataset is produced we refer to GloFAS forecast skill. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
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GloFAS Seasonal ForecastsThis dataset provides a gridded modelled time series of river discharge, forced with seasonal range meteorological forecasts from GloFAS. This dataset was produced by forcing the LISFLOOD hydrological model at a 0.1° (~11 km at the equator) resolution with downscaled runoff forecasts from the ECMWF 51-member ensemble seasonal forecasting system, SEAS5. The forecasts are initialised on the first of each month with a 24-hourly time step, and cover 123 or 215 days, depending on the data it was produced. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
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GloFAS Seasonal reforecastsThis dataset provides a gridded modelled time series of river discharge forced with seasonal range meteorological reforecasts from GloFAS. This dataset was produced by forcing the LISFLOOD hydrological modelling chain with input from the ECMWF ensemble seasonal forecasting system, SEAS5. For the period of 1981 to 2016 the number of ensemble members is 25, whilst reforecasts produced for 2017 onwards use a 51-member ensemble. Reforecasts are forecasts run over past dates, with those presented here used for producing the seasonal river discharge thresholds. In addition, they provide a suitably long time period against which the skill of the seasonal forecast can be assessed. The reforecasts are initialised monthly and run with 24-hourly time step for 123 days or 215 days, depending on the date it was produced. For more specific information on the how the seasonal reforecast dataset is produced we refer to the documentation. Data can be accessed is several ways, the most common is through the CDS (see Data Access).
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GloFAS variables
GloFAS variables (called 'parameters' in ECMWF MARS) are the hydrological entities calculated by the modelling chain.
From GloFAS v4.1, the following variables are made available:
- River discharge in the last 24 hours,
- Soil wetness index (root zone) (see Soil wetness index (root zone) for details),
- Runoff water equivalent (surface plus subsurface),
- Snow depth water equivalent.
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For previous GloFAS versions, only the variable 'River discharge in the last 24 hours' was available. |
A short description of variables is given below in table below, along with associated metadata information.
GloFAS Short Description | Unit | GRIB parameter ID | GRIB Short name | GRIB Name | Comment | GRIB description | CDS description |
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| River discharge in the last 24 hours | m3/s | 240024 | dis24 | Mean discharge in the last 24 hours | Average | Volume rate of water flow, including sediments, chemical and biological material, in the river channel averaged over a time step through a cross-section. | Same as GRIB description |
Soil wetness index (see Soil wetness index (root zone) for details) | Numeric | 231026 | swir | Soil wetness index (root zone) | Instantaneous at the end of the model time step | The volume of water over the total volume of voids in the soil, expressed as an index with values between 0 (residual soil moisture) and 1 (saturation), representing the lower and upper soil moisture limits of the root zone. The root zone is the maximum depth at which plants can extract water from the soil. Voids are empty spaces in the soil column that can be filled with water or air. | The volume of water over the total volume of voids in the soil, expressed as an index with values between 0 (residual soil moisture) and 1 (saturation), representing the lower and upper soil moisture limits of the root zone. The root zone is the maximum depth at which plants can extract water from the soil. Voids are empty spaces in the soil column that can be filled with water or air. |
Runoff water equivalent | kg/m2 | 231002 | rowe | Runoff water equivalent (surface plus subsurface) | Accumulation | Some water from rainfall, melting snow, or deep in the soil, stays stored in the soil. Otherwise, the water drains away, either over the surface (surface runoff), or under the ground (sub-surface runoff) and the sum of these two is simply called 'runoff'. This parameter is the total amount of water accumulated over a particular time period which depends on the data extracted.The units of runoff are depth in metres. This is the depth the water would have if it were spread evenly over the grid box. Care should be taken when comparing model parameters with observations, because observations are often local to a particular point rather than averaged over a grid square area. Observations are also often taken in different units, such as mm/day, rather than the accumulated metres produced here. | The sum of the surface and sub-surface runoff, and represents all the water that would drain away from the grid box. This variable is the total amount of water accumulated from the beginning of the time step to the end of the time step. |
| Snow depth water equivalent | kg/m2 | 228141 | sd | Snow depth water equivalent | Instantaneous at the end of the model time step | Snow depth water equivalent in kg m**-2 (mm) water equivalent | The mass of water per square meter if all the snow in the grid box would be melted. The value is instantaneous meaning that it is valid for the last time step of the integration at the issued model time step |
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GloFAS variable river discharge (dis) is stored as average over the time step of the model (24-hourly), with time stamp (date and time of end of averaging period) explicit in the GRIB short name. In GloFAS, river discharge is calculated in each grid box of the hydrological model. However, not all grid boxes correspond to a river segment, and because of the relatively coarse resolution of the GloFAS gridded domain, the modelled river network in GloFAS might be associated with slightly different latitude-longitude than in the real world. It is hence essential that when extracting river discharge data, the user also checks the upstream area of the grid box of interest. The GloFAS upstream area can be found in the Auxiliary Data pages. Some short scripts to use as examples are provided in the Working with CEMS-Flood Data pages. |
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Snow depth water equivalent represents the amount of water stored as ice and snow given as an instantaneous value at the end of each model time step. In GloFAS, snow depth water equivalent in each grid box is calculated from three elevation-related bands to account for the difference in the melting rate with snow condition (see Auxiliary Data for more details). However, only the more directly usable composite snow map representing the total snow water equivalent for each grid box is made available. Some short scripts to use as examples are provided in the Working with CEMS-Flood Data pages. |
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Soil wetness index (root zone) represents the volume of water stored in the soil layers given as an instantaneous value at the end of each model time step. GloFAS soil wetness information is stored as the fraction of the total volume of voids in the root zone. The root zone is the maximum depth at which plants can extract water from the soil. Voids are empty spaces in the soil column that can be filled with water or air. See Soil wetness index (root zone) for details. |
GLOFAS Short Description
Unit
GRIB Short name
GRIB Name
GRIB description
m3/s
dis24
Mean discharge in the last 24 hours
Average
Volume rate of water flow, including sediments, chemical and biological material, in the river channel averaged over a time step through a cross-section.
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Runoff water equivalent (surface and subsurface) represents the sum of the surface and sub-surface runoff, and represents all the water that would drain away from the grid box. This variable is the total amount of water accumulated from the beginning of the time step to the end of the time step. GloFAS NOTE: If this variable were to be expressed as a value over the time step (e.g. 'runoff over the last 24 hours), it would become an average flux. |
Recommendation regarding GloFAS outputs
GloFAS is primarily designed for larger river catchments (over 10,000 km2), where the forecast skill is expected to be considerably higher. For small catchments, especially below 500 km2, the uncertainties get much larger due to the horizontal resolution constraints (~5 km in the river network and ~9 km in the meteorological forcing such as precipitation). This is reflected in our products/layers which do consider a minimum catchment size of 250 km2 or 500 km2, depending on the product.