In order to interpret CEMS-Flood (EFAS & GloFAS) model outputs in a correct way, you will need a number of auxiliary data, also referred to as the 'time invariant' data on the Climate Data Store (CDS). These data are part of the EFAS and GloFAS setups of the LISFLOOD model. This page summarises the auxiliary datasets made available through the CDS and how they should be used in combination with the model outputs.
EFAS Auxiliary Data
The auxiliary data are provided as small (no larger than 8MB) netCDF files, and are available to download through the Climate Data Store (CDS) on the EFAS pages.
They are in the INSPIRE compliant ETRS89 Lambert Azimuthal Equal Area Coordinate Reference System (ETRS-LAEA), also referred to as EPSG:3035. More information on the EFAS horizontal resolution is available in the model output page.
It is important for users to make sure they download the auxiliary data consistent with the dataset version of interest. This is because the auxiliary data sometimes change with a new EFAS cycle; for example, the upstream area is specific to the hydrological model configuration used which can change between cycles.
To provide an example, users accessing forecast data issued between 2019-05-13 and 2020-03-04 should use v3.0 of the auxiliary data, as forecasts issued during that period were produced with EFAS v3.0. All the version dates are shown in the table below:
| Versions | For forecast data issued from: |
|---|---|
| EFAS version 4.0 | 2020-10-14 12 UTC to present |
| EFAS version 3.5 | 2020-03-05 12 UTC and 2020-10-13 12 UTC |
| EFAS version 3.0 | 2019-05-13 12 UTC and 2020-03-04 12 UTC |
| EFAS version 2.0 | before 2019-05-13 12 UTC |
The upstream area file denotes the total upstream area for each river pixel, expressed in m2. It is defined as the catchment area for each river segment, i.e. the total area that contributes with water to the river at the specific grid point (or river pixel). The upstream area always includes the area of the pixel it is associated to.
The elevation (sometimes referred to as orography) file denotes the mean elevation for each pixel in the EFAS domain, expressed in m above sea level. It is defined for each grid point of the modelled domain.
The files for soil depth, wilting capacity, and field capacity are collectively known as the 'soil moisture index files', and contain all the relevant information to calculate the soil moisture index from the volumentric soil moisture dataset model output. They are provided separately for each of the three soil layers represented in LISFLOOD.
More detail on the datasets and how they should be used to derive the soil moisture index is provided here.
GloFAS Auxiliary Data
In order to interpret the GloFAS output in a correct way, you will need static data that describes the model setup. This file denotes the total upstream area for each river pixel, expressed in m2. The upstream area is defined as the catchment area for each river segment, in other words, the total area that contributes water to the river at the specific grid point. The upstream area always includes the area of the pixel. You can download the upstream area file as a netCDF file here: upArea (1).nc.