Global Mean
Main concepts
The global_mean command is based on the global_mean.py script which computes the global averages for many dynamical and physical fields.
It compares the output against a set of pre-computed climatological values defined in the reference climatology (see below) and produces a table with the comparison.
This includes the most important dynamical and physical fields for both the atmosphere and the ocean (e.g. land temperature, salinity, etc.).
Different datasets are taken in consideration, providing an estimate of the interannual variability in the form of standard deviation.
Most importantly, it provides estimates for the radiative budget (including clouds radiative forcing) and for the hydrological cycle (including integrals over land and ocean) and other quantities useful for fast model assessment and for model tuning.
Usage
Running the global mean evaluation is rather simple:
global_mean EXP Y1 Y2
Alternatively, you can also run the python script in ecmean library:
./global_mean.py EXP Y1 Y2
Positional Arguments
- EXP
Experiment identification.
- Y1
Starting year of analysis.
- Y2
Final year of analysis.
Optional Arguments
- -h, --help
Show this help message and exit.
- -s, --silent
Do not print anything to standard output.
- --version
Show ECmean’s version number and exit.
- -l LOGLEVEL, --loglevel LOGLEVEL
Define the level of logging. The default is ‘warning’.
- -j NUMPROC
Specify the number of processors to use.
- -c CONFIG, --config CONFIG
Set up a specific configuration file. The default is
config.yml.
- -i INTERFACE, --interface INTERFACE
Set up a specific interface file, overriding the configuration specified in
config.yml.
- -m MODEL, --model MODEL
Specify the model name, overriding the configuration specified in
config.yml.
- -e ENSEMBLE, --ensemble ENSEMBLE
Specify the variant label (ripf number for cmor).
- -o DIR, --outputdir DIR
Specify the path of the output directory. This will create YAML and PDF folders for tables and figures.
- --reference REFERENCE
Specify the reference dataset to use for comparison. The default is EC23. Other options include EC26-HIST, EC26-PDAY, and EC26-CMIP.
- --trend
Compute trends on multiple years. This option is only available in table format.
- --line
Append a single line to the table.
- --addnan
Activate to plot also in the heatmap also fields which does not have a comparison against observations. Default is False.
Example
Usage example for CMIP5:
global_mean historical 1990 1999 -j 12 -m EC-EARTH -e r1i1p1 -i CMIP5
This will compute the global mean for member r1i1p1 of the EC-EARTH model in the CMIP5 historical experiment.
Output
Data are stored in machine-readable format in a YAML file, which includes much more details such as the global and regional mean over different seasons. In addition, ECmean produces also a figure including a more detailed comparison for different seasons and regions. This is available only for the datasets for which we have access to a gridded dataset.
An example for a single year of the EC-Earth3 historical r1i1p1f1 simulation. Colors indicate the model bias as standard deviation of the interannual variability from observations. Blue implies negative bias, red positive bias. In each of the tiles the larger number shows the model value, while the smaller one is the reference value.
Finally, a txt table including the comparison with some predefined dataset, for the global mean yearly averages.
References available
Currently, two main different references for climatological values are available, EC26 and EC23, covering different observation periods.
EC26
EC26 is the updated reference framework for global mean observational datasets, which provide a flexible framework for evaluating climate models. It provides temporally consistent baselines tailored to different model forcing configurations, declined in three configurations (CMIP, HIST, PDAY) to match the intended timeframes. It also includes a global near-surface air temperature target, which was not available in the older reference. The variables are derived from a combination of observational and reanalysis products (e.g. CRU v4.09, Berkeley Earth, ERA5, MSWEP v2.80, CERES EBAF v4.2.1, ESA-CCI), depending on the physical quantity considered.
All configurations share the same variable definitions and masking strategy (global, land, ocean), but differ in their temporal averaging window to ensure consistency with the intended model experiments. All metadata (datasets, masks, periods and other properties) are defined in the corresponding YAML configuration file.
EC26-CMIP (1985–2014)
This reference dataset is designed for the evaluation of CMIP6 historical simulations against a consistent observational baseline. It is aligned with the CMIP6 historical period (1985–2014), ensuring temporal consistency between model climatologies and observational targets. Radiative fluxes are restricted to the satellite era (2000–2014), while ocean salinity follows its specific observational availability window.
Long Name |
Dataset |
Mask |
Period |
|---|---|---|---|
2m Temperature (land-only) |
CRU (v4.09) |
land-no-antarctica |
1985-2014 |
2m Temperature |
BERKELEY-EARTH |
global |
1985-2014 |
Mean Sea Level Pressure |
ERA5 |
global |
1985-2014 |
Precipitation |
MSWEP (v2.80) |
global |
1985-2014 |
Evaporation |
ERA5 |
global |
1985-2014 |
Precip. minus Evap. |
ERA5 |
global |
1985-2014 |
Total Cloud Cover |
EBAF_v4.2.1 (v4.2.1) |
global |
2000-2014 |
Low Cloud Cover |
ERA5 |
global |
1985-2014 |
Medium Cloud Cover |
ERA5 |
global |
1985-2014 |
High Cloud Cover |
ERA5 |
global |
1985-2014 |
Precipitation (ocean) |
MSWEP (v2.80) |
ocean |
1985-2014 |
Precip. minus Evap. (ocean) |
ERA5 |
ocean |
1985-2014 |
Precipitation (land) |
MSWEP (v2.80) |
land |
1985-2014 |
Precip. minus Evap. (land) |
ERA5 |
land |
1985-2014 |
TOA Net |
CERES EBAF (v4.2.1) |
global |
2000-2014 |
TOA SW Net |
CERES EBAF (v4.2.1) |
global |
2000-2014 |
TOA LW Net |
CERES EBAF (v4.2.1) |
global |
2000-2014 |
TOA SW Net (clear sky) |
CERES EBAF (v4.2.1) |
global |
2000-2014 |
TOA LW Net (clear sky) |
CERES EBAF (v4.2.1) |
global |
2000-2014 |
SW Cloud Forcing |
CERES EBAF (v4.2.1) |
global |
2000-2014 |
LW Cloud Forcing |
CERES EBAF (v4.2.1) |
global |
2000-2014 |
Surface Net SW |
Wild 2020 |
global |
|
Surface Net LW |
Wild 2020 |
global |
|
Surface Sensible Heat Flux |
Wild 2020 |
global |
|
Surface Latent Heat Flux |
Wild 2020 |
global |
|
Net Surface (no snowfall) |
Wild 2020 |
global |
|
Net Surface |
Wild 2020 |
global |
|
TOA - Sfc Net Radiation (no snow) |
None |
global |
|
TOA - Sfc Net Radiation |
None |
global |
|
Sea Surface Temperature |
ESA-CCI-L4 (v3.0.1) |
ocean |
1985-2014 |
Sea Surface Salinity |
Copernicus Global Analysed Sea Surface Salinity |
ocean |
1993-2014 |
SSH |
None |
global |
|
Net Water Flux into ocean |
None |
global |
|
Sea Ice Area |
ESA-CCI-L4 (v3.0.1) |
ocean |
1985-2014 |
EC26-HIST (1981–2010)
This configuration is designed for comparison with model simulations using historical forcing or present-day forcing fixed around 1990. The reference period spans 1981–2010 where observational coverage allows. Radiative fluxes follow the CERES satellite era (starting in 2000), while other variables use the 1981–2010 window.
Long Name |
Dataset |
Mask |
Period |
|---|---|---|---|
2m Temperature (land-only) |
CRU (v4.09) |
land-no-antarctica |
1981-2010 |
2m Temperature |
BERKELEY-EARTH |
global |
1981-2010 |
Mean Sea Level Pressure |
ERA5 |
global |
1981-2010 |
Precipitation |
MSWEP (v2.80) |
global |
1981-2010 |
Evaporation |
ERA5 |
global |
1981-2010 |
Precip. minus Evap. |
ERA5 |
global |
1981-2010 |
Total Cloud Cover |
EBAF_v4.2.1 (v4.2.1) |
global |
2000-2010 |
Low Cloud Cover |
ERA5 |
global |
1981-2010 |
Medium Cloud Cover |
ERA5 |
global |
1981-2010 |
High Cloud Cover |
ERA5 |
global |
1981-2010 |
Precipitation (ocean) |
MSWEP (v2.80) |
ocean |
1981-2010 |
Precip. minus Evap. (ocean) |
ERA5 |
ocean |
1981-2010 |
Precipitation (land) |
MSWEP (v2.80) |
land |
1981-2010 |
Precip. minus Evap. (land) |
ERA5 |
land |
1981-2010 |
TOA Net |
CERES EBAF (v4.2.1) |
global |
2000-2010 |
TOA SW Net |
CERES EBAF (v4.2.1) |
global |
2000-2010 |
TOA LW Net |
CERES EBAF (v4.2.1) |
global |
2000-2010 |
TOA SW Net (clear sky) |
CERES EBAF (v4.2.1) |
global |
2000-2010 |
TOA LW Net (clear sky) |
CERES EBAF (v4.2.1) |
global |
2000-2010 |
SW Cloud Forcing |
CERES EBAF (v4.2.1) |
global |
2000-2010 |
LW Cloud Forcing |
CERES EBAF (v4.2.1) |
global |
2000-2010 |
Surface Net SW |
Wild 2020 |
global |
|
Surface Net LW |
Wild 2020 |
global |
|
Surface Sensible Heat Flux |
Wild 2020 |
global |
|
Surface Latent Heat Flux |
Wild 2020 |
global |
|
Net Surface (no snowfall) |
Wild 2020 |
global |
|
Net Surface |
Wild 2020 |
global |
|
TOA - Sfc Net Radiation (no snow) |
None |
global |
|
TOA - Sfc Net Radiation |
None |
global |
|
Sea Surface Temperature |
ESA-CCI-L4 (v3.0.1) |
ocean |
1981-2010 |
Sea Surface Salinity |
Copernicus Global Analysed Sea Surface Salinity |
ocean |
1993-2010 |
SSH |
None |
global |
|
Net Water Flux into ocean |
None |
global |
|
Sea Ice Area |
ESA-CCI-L4 (v3.0.1) |
ocean |
1981-2010 |
EC26-PDAY (2000–2024)
This configuration is intended for evaluation of model simulations using present-day forcing conditions representative of the 2010–2012 period. The reference period spans 2000–2024 (or the maximum available year depending on dataset availability; e.g. 2023 for ESA-CCI-L4 products). By using a more recent averaging window, EC26-PDAY reflects contemporary radiative balance and hydrological cycle conditions, making it suitable for fixed present-day forcing experiments.
Long Name |
Dataset |
Mask |
Period |
|---|---|---|---|
2m Temperature (land-only) |
CRU (v4.09) |
land-no-antarctica |
2000-2024 |
2m Temperature |
BERKELEY-EARTH |
global |
2000-2024 |
Mean Sea Level Pressure |
ERA5 |
global |
2000-2024 |
Precipitation |
MSWEP (v2.80) |
global |
2000-2024 |
Evaporation |
ERA5 |
global |
2000-2024 |
Precip. minus Evap. |
ERA5 |
global |
2000-2024 |
Total Cloud Cover |
EBAF_v4.2.1 (v4.2.1) |
global |
2000-2024 |
Low Cloud Cover |
ERA5 |
global |
2000-2024 |
Medium Cloud Cover |
ERA5 |
global |
2000-2024 |
High Cloud Cover |
ERA5 |
global |
2000-2024 |
Precipitation (ocean) |
MSWEP (v2.80) |
ocean |
2000-2024 |
Precip. minus Evap. (ocean) |
ERA5 |
ocean |
2000-2024 |
Precipitation (land) |
MSWEP (v2.80) |
land |
2000-2024 |
Precip. minus Evap. (land) |
ERA5 |
land |
2000-2024 |
TOA Net |
CERES EBAF (v4.2.1) |
global |
2000-2024 |
TOA SW Net |
CERES EBAF (v4.2.1) |
global |
2000-2024 |
TOA LW Net |
CERES EBAF (v4.2.1) |
global |
2000-2024 |
TOA SW Net (clear sky) |
CERES EBAF (v4.2.1) |
global |
2000-2024 |
TOA LW Net (clear sky) |
CERES EBAF (v4.2.1) |
global |
2000-2024 |
SW Cloud Forcing |
CERES EBAF (v4.2.1) |
global |
2000-2024 |
LW Cloud Forcing |
CERES EBAF (v4.2.1) |
global |
2000-2024 |
Surface Net SW |
Wild 2020 |
global |
|
Surface Net LW |
Wild 2020 |
global |
|
Surface Sensible Heat Flux |
Wild 2020 |
global |
|
Surface Latent Heat Flux |
Wild 2020 |
global |
|
Net Surface (no snowfall) |
Wild 2020 |
global |
|
Net Surface |
Wild 2020 |
global |
|
TOA - Sfc Net Radiation (no snow) |
None |
global |
|
TOA - Sfc Net Radiation |
None |
global |
|
Sea Surface Temperature |
ESA-CCI-L4 (v3.0.1) |
ocean |
2000-2023 |
Sea Surface Salinity |
Copernicus Global Analysed Sea Surface Salinity |
ocean |
2000-2024 |
SSH |
None |
global |
|
Net Water Flux into ocean |
None |
global |
|
Sea Ice Area |
ESA-CCI-L4 (v3.0.1) |
ocean |
2000-2023 |
EC23
This is from the old version of ECmean and does not include values for global tas. This reference dataset collects global mean observational targets used by the global_mean.py script to compute global averages. The variables are derived from a combination of observational and reanalysis products (e.g. CRU, ERA5, MSWEP, CERES-EBAF, ESA-CCI, Wild 2020), depending on the physical quantity considered. Most fields are defined over the 1991–2020 period, while other variables use shorter observational windows due to data availability. All metadata (datasets, masks, periods and other properties) are defined in the corresponding YAML configuration file.
Long Name |
Dataset |
Mask |
Period |
|---|---|---|---|
2m Temperature (land-only) |
CRU |
land-no-antarctica |
1991-2020 |
Mean Sea Level Pressure |
ERA5 |
global |
1991-2020 |
Precipitation |
MSWEP |
global |
1991-2020 |
Evaporation |
ERA5 |
global |
1991-2020 |
Precip. minus Evap. |
ERA5 |
global |
1991-2020 |
Total Cloud Cover |
CERES-EBAF |
global |
2000-2020 |
Low Cloud Cover |
ERA5 |
global |
1991-2020 |
Medium Cloud Cover |
ERA5 |
global |
1991-2020 |
High Cloud Cover |
ERA5 |
global |
1991-2020 |
Precipitation (ocean) |
MSWEP |
ocean |
1991-2020 |
Precip. minus Evap. (ocean) |
ERA5 |
ocean |
1991-2020 |
Precipitation (land) |
MSWEP |
land |
1991-2020 |
Precip. minus Evap. (land) |
ERA5 |
land |
1991-2020 |
TOA Net |
CERES-EBAF |
global |
2000-2020 |
TOA SW Net |
CERES-EBAF |
global |
2000-2020 |
TOA LW Net |
CERES-EBAF |
global |
2000-2020 |
TOA SW Net (clear sky) |
CERES-EBAF |
global |
2000-2020 |
TOA LW Net (clear sky) |
CERES-EBAF |
global |
2000-2020 |
SW Cloud Forcing |
CERES-EBAF |
global |
2000-2020 |
LW Cloud Forcing |
CERES-EBAF |
global |
2000-2020 |
Surface Net SW |
Wild 2020 |
global |
|
Surface Net LW |
Wild 2020 |
global |
|
Surface SH |
Wild 2020 |
global |
|
Surface LH |
Wild 2020 |
global |
|
Net Surface (no snowfall) |
Wild 2020 |
global |
|
Net Surface |
Wild 2020 |
global |
|
Sea Surface Temperature |
ESA-CCI-L4 |
ocean |
1991-2020 |
Sea Surface Salinity |
ESA-CCI |
ocean |
2010-2020 |
SSH |
None |
global |
|
Net Water Flux into ocean |
None |
global |
|
TOA - Sfc Net Radiation (no snow) |
None |
global |
|
TOA - Sfc Net Radiation |
None |
global |
|
Sea Ice Area |
ESA-CCI-L4 |
ocean |
1991-2020 |
Sea Ice Area (Northern Hemisphere) |
ESA-CCI-L4 |
north |
|
Sea Ice Area (Southern Hemisphere) |
ESA-CCI-L4 |
south |
Reference climatology computation
Reference climatology are computed by the ecmean/utils/reference-create.py script, which is included in the repository for documentation.
It is based on a YML file which is tells the script where to retrieve the data, identifying all the required data folder and names.
Of course, in the remote case you would like to develop a new climatology, you can create your own YML file and run the script to produce the reference climatology
Examples are the create-reference-wilma-EC26.yml and create-reference-wilma-EC23.yml files, which are used to produce the EC26 and EC23 reference climatology, respectively.
The results are produced into a YML file for in ecmean/reference/gm_reference_EC**.yml which includes the global and regional mean
over different seasons as well the interannual standard deviation. Full details on the datasets used are found there.