Questions related to data outputs from the EURO-CORDEX RCMs. Which kind of data exist, which variables are stored, for which levels and at what time intervals.
What is the climate model output representative of?
Climate models calculates the evolution of the state of the climate system over time in relatively short time steps (minutes to hours) on a spatial grid with grid spacing of tens to hundreds of kilometers.
In some more detail, climate models produce output data for a number of variables describing the state of the atmosphere, including temperature, humidity, air pressure and wind speed. These variables are calculated prognostically at a large number of vertical levels. In addition, a number of fluxes are calculated including fluxes of momentum, energy, humidity in the atmosphere and between the atmosphere and the surface that can be either ground or ocean. Also, a number of sub-grid scale features, including cloud properties, radiation processes, precipitation processes are also calculated. such as cloud droplet concentration and cloud water and cloud ice content. The amount of output data that is stored in the simulations may differ between different RCM groups. Most often, a minimum set of variables is stored in order to compare single RCM projections to others.
What RCM-data is available at the CDS?
Output data from the RCMs are usually stored at intervals of once per day or once per three hours.
For the EURO-CORDEX data provided through the CDS see: https://confluence.ecmwf.int/display/CKB/CORDEX%3A+Regional+climate+projections
For a list of available variables and time steps see: https://cds.climate.copernicus.eu/cdsapp#!/dataset/projections-cordex-domains-single-levels)
In the process of running climate models it can be decided which variables to store, and at what temporal resolution or vertical levels. The result is often a compromise between user requirements and the availability of storage space. In some cases, it is possible that also other variables, or data at higher temporal resolution or other vertical levels, are stored locally by the group that produced a particular RCM run. Such data may be available from the producers upon request.
