Climatologies and climatological anomalies have been calculated at CEDA from CMIP5 model output.

Time Periods:
- AR5 averaging periods: 2016-2035, 2046-2065, 2081-2100

Anomaly Specification:
All values are taken as anomalies from the 1986->2005 mean (base line values).

Output:
- Period mean of the monthly mean of the variables
- 12 monthly values per climatology
- Climatology is a 2D field
- One climatology per model per scenario per variable per time period
- CF compliant netCDF files

Directory Structure:
The output directory structure follows the DRS specification with the root directory being /derived.
Each file has the extended attribute: clim-anom-ref5. This indicates that it is a climatological mean anomaly (clim-anom) and that the reference period matches the AR5 reference period (ref5).

Method:
The algorithm follows the process below:

- For every model:
- For every variable (if available):
calculate the 1986->2005 climatological (period average) monthly means (baseline) for the Historical experiment

- For every model:
- For every variable (if available):
calculate the period average monthly means (baseline) of the last 20 years of the piControl run

- For every model:
- For every experiment:
- For every time period:
- For every variable (if available):
calculate the climatological monthly mean for this (model, experiment, time period, variable) and subtract the relevant baseline

Code:
https://github.com/cedadev/ipcc_ddc_cmip5_clim_anoms/releases/tag/1.0