This catalogue entry dataset provides daily and monthly Regional Climate Model (RCM) data on single levels from a number of experiments, models , members and time periods computed in the framework of the Coordinated Regional Climate Downscaling Experiment (CORDEX). The term "single levels" is used to express that the variables are computed at one vertical level which can be surface (or a level close to the surface) or a dedicated pressure level in the atmosphere. Multiple vertical levels are excluded from this catalogue entry.
High-resolution RCMs can provide climate change projection information on regional and local scales in relatively fine detail, which cannot be obtained from coarse scale lower resolution Global Climate Models (GCMs). This is manifested in better description more realistic descriptions of small-scale regional climate characteristics and also in more accurate representation of including extreme events. Consequently, outputs of such RCMs are indispensable important in supporting regional and local climate impact studies and adaptation decisions. RCMs are not independent from the GCMs, since the GCMs provide lateral and lower boundary conditions to the regional models. In that sense RCMs can be viewed as magnifying glasses of the GCMs.
The CORDEX experiments consist of a large number of RCM simulations representing different future forcing scenariossocio-economic scenarios (forcings), different combinations of GCMs and RCMs and different ensemble members of the same GCM-RCM combinations. This experiment design through the ensemble members allows for studies addressing questions related to the key uncertainties in future climate change:
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. These uncertainties come from differences in the scenarios of future socio-economic development, the imperfection of regional and global models used and the internal (natural) variability of the climate system
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The term "experiment" in the CDS form refers to distinguishes between three main simulation categories:
- Evaluation: CORDEX experiment driven by ECMWF ERA-Interim reanalysis for a past period. These experiments can be used to evaluate the quality of the RCMs using perfect boundary conditions as provided by a reanalysis system. The period covered is typically 1980-2010;
- Historical: CORDEX experiment which covers driven by boundary conditions provided by GCMs. These experiments cover a period for which modern climate observations exist. Boundary conditions are provided by GCMs. These experiments , that follow the observed changes in climate forcing, show how the RCMs perform for the past climate when forced by GCMs and can be used as a reference period for comparison with scenario runs for the future. The period covered is typically 1950-2005.;
- Scenario (RCP2.6, RCP4.5, RCP8.5): Ensemble of CORDEX climate projection experiments driven by boundary conditions from GCMs using RCP (Representative Concentration Pathways) forcing scenarios. These The scenarios used here are the RCP 2.6, 4.5 and 8.5 scenarios providing they provide different pathways of the future climate forcing. Boundary conditions are provided by GCMs. The period covered is typically 2006-2100.
In CORDEX, the same experiments were done run using different RCMs (labelled as “Regional Climate Model” in the CDS form).In addition, for each RCM, there is . Each RCM uses a variety of GCMs , which can be used as lateral boundary conditions. The GCMs used are coming from the CMIP5 (5th phase of the Coupled Model Intercomparison Project) archive. These GCM boundary conditions are labelled as “Global Climate Model” in the form. Note that CMIP5 GCM datasets are also available in the CDS.
Additionally, the uncertainty related to internal variability of the climate system is sampled by several members of a few running several simulations with the same RCM-GCM combinationscombination. Each member of the ensemble is named after a triad of integers associated to the letters r (as realization), i (as initialization) and p (as physics representing parameter settings in the models). These three letters cover variations in initial conditions as well as in the physical parameters of the models. The associated numbers are typically assigned sequentially. For instance, the member "r1i1p1" and the member "r2i1p1" being two realizations for the same model and experiment indicate that the corresponding simulations differ only in which GCM realization that has been downscaled. Different GCM realizations, in turn, differ only in definition of the initial conditions applied as being representative of the pre-industrial time, i.e. typically 1850. More details behind these sequential ensemble numbers will be available in the detailed documentation.This dataset is planned to be updated regularly when new RCM simulations will be available in the CORDEX databaseOn the forms, these are indexed as separate ensemble members (the naming convention for ensemble members is available in the documentation).
The data are produced by the participating institutes of the EURO-CORDEX project (see more details at the documentation section).
More details about the product are given in the Documentation section.