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The models included in the CDS-CORDEX subset are detailed in the table below, these include 12 of the models from the main CORDEX archive. However a small number of models were not included as the data from the models have a research-only restriction on their use, all data in the CDS are released without restriction. 

The CDS-CORDEX subset also include a version number. This integer identifies the version of the RCM simulations/run and not the version of the RCM itself. All models runs start with "v1" but new runs can occur for many reasons or computing errors. Runs numbers different from “v1” means new simulations relative to the first “v1” one. It might not mean a new version.

Driving Global Models

The driving GCMs used to produced the CDS-CORDEX subset are details in the table below, these include 8 of the models from the main CMIP5 archive. However a small number of models were not included as the data from the models have a research-only restriction on their use, all data in the CDS are released without restriction.

Ensembles

Each modelling The boundary conditions used to run a RCM are also identified by the model member if the CMIP5 simulation used. Each modeling centre will typically run the same experiment using the same model GCM several times to confirm the robustness of results and inform sensitivity studies through the generation of statistical information. A model and its collection of runs is referred to as an ensemble. Within these ensembles, three different categories of sensitivity studies are done, and the resulting individual model runs are labelled by three integers indexing the experiments in each category. 

• The first category, labelled “realization”, performs experiments which differ only in random perturbations of the initial conditions of the experiment. Comparing different realizations allow estimation of the internal variability of the model climate. 
• The second category refers to variation in initialisation initialization parameters. Comparing differently initialised initialized output provides an estimate of how sensitive the model is to initial conditions. 
• The third category, labelled “physics”, refers to variations in the way in which sub-grid scale processes are represented. Comparing different simulations in this category provides an estimate of the structural uncertainty associated with choices in the model design. 

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It is very important to distinguish between variations in experiment specifications, which are globally coordinated across all the models contributing to CMIP5, and the variations which are adopted by each modelling modeling team to assess the robustness of their own results. The “p” index refers to the latter, with the result that values have different meanings for different models, but in all cases these variations must be within the constraints imposed by the specifications of the experiment. 

For the scenario experiments, the ensemble member identifier is preserved from the historical experiment providing the initial conditions, so RCP 4.5 ensemble member “r1i1p2” is a continuation of historical ensemble member “r1i1p2”.

On a general level in the CDS form for the RCM simulations “v” enumerates runs and NOT model versions. For the DMI, KNMI and SMHI runs numbers different from “v1” means new simulations relative to the first “v1” one. It might not mean a new version.

• DMI

1. For the EC-EARTH r3i1p1 forced HIRHAM simulation “v2” is a new simulation where proper GHG concentrations changing with time are used as a contrast to “v1” that erroneously used the constant control level throughout the simulation. Therefore users should use v2.
2. As it is for point 1. “v2” is used for the HIRHAM simulation forced by MOHC-HadGEM2-ES.
3. As for the previous two points but here “v3” is used for the NorESM driven simulation. A previous “v2” version including also an error in the vertical interpolation when preparing the boundary files also exists.

• KNMI

1. For the MOHC-HadGEM2-ES forced RACMO simulation v2 is a new simulation where a big error in SST-remapping from the HadGEM-grid to the RCM-grid in v1 was corrected. The erroneous v1-simulation has been unpublished from the ESGF.
2. For the CNRM-CM5 simulation v2 is a new simulation replacing the old now with input data taken from pressure levels instead of model levels. The originally provided model level fields from CNRM were wrong.

• SMHI

1. Two MPI-driven scenario runs were rerun in 2016 as there had been problems with a restart file and as there was an error in the snow diagnostics in the original run. The reruns were labelled v1a.

• CNRM

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For CORDEX data, the ensemble member is equivalent to the ensemble member of the CMIP5 simulation used to extract boundary conditions.

File naming conventions

When you download a CORDEX file from the CDS it will have a naming convention that is as follows:

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