GEOS-Chem required disk space
- Minimum system requirements for GEOS-Chem
- Installing required software
- Configuring your computational environment
- Downloading source code
- Downloading data directories
- Creating run directories
- Configuring runs
- Output files
- Python tools for use with GEOS-Chem
- Coding and debugging
- Further reading
Input data for GEOS-Chem
The following sections will help you assess how much disk space you need to run GEOS-Chem.
Please see our HEMCO data directories page to see how much disk space each of the emissions inventory requires. Emissions inventories will be read into GEOS-Chem by the Harmonized Emissions Component (aka HEMCO).
The amount of disk space that you will need depends on two things:
- Which type of met data you will use, and
- How many years of met data you will download
Typical disk space requirements are:
|Met field||Resolution||File type||Size|
|MERRA-2||4° x 5°||COARDS-compliant netCDF (compressed)||~ 30 GB/yr|
|MERRA-2||2° x 2.5°||COARDS-compliant netCDF (compressed)||~ 110 GB/yr|
|MERRA-2||0.5° x 0.625 Asia ("AS") nested grid||COARDS-compliant netCDF (compressed)||~ 115 GB/yr|
|MERRA-2||0.5° x 0.625 Europe ("EU") nested grid||COARDS-compliant netCDF (compressed)||~ 58 GB/yr|
|MERRA-2||0.5° x 0.625 North America ("NA") nested grid||COARDS-compliant netCDF (compressed)||~ 110 GB/yr|
|GEOS-FP||4° x 5°||COARDS-compliant netCDF (compressed)||~ 30 GB/yr|
|GEOS-FP||2° x 2.5°||COARDS-compliant netCDF (compressed)||~ 120 GB/yr|
|GEOS-FP||0.25° x 0.3125° China ("CH") nested grid||COARDS-compliant netCDF (compressed)||~ 175 GB/yr|
|GEOS-FP||0.25° x 0.3125° Europe ("EU") nested grid||COARDS-compliant netCDF (compressed)||~ 58 GB/yr|
|GEOS-FP||0.25° x 0.3125° North America ("NA") nested grid||COARDS-compliant netCDF (compressed)||~ 226 GB/yr|
Obtaining emissions data and met fields
You can use a GEOS-Chem "dry-run" simulation to only download as many emissions inventories and met field data files as your simulation needs. For more information, please see our chapter on Downloading data with the GEOS-Chem dry-run option.
Data generated by GEOS-Chem
For the full-chemistry simulations, we can look to the GEOS-Chem benchmarks as a rough upper limit of how much disk space is needed for diagnostic output. The GEOS-Chem 13.0.0 vs. 12.9.0 1-month benchmark simulation generated approximately 837 MB/month of output. Of this amount, monthly-mean diagnostic output accounted for ~646 MB and restart files (generated at the end of the simulation) accounted for ~191 MB.
We say that this is an upper limit, because benchmark simulations archive the "kitchen sink"—all species concentrations, various aerosol diagnostics, convective fluxes, dry dep fluxes and velocities, J-values, various chemical and meteorological quantities, transport fluxes, wet deposition diagnostics, and emissions diagnostics. Most GEOS-Chem users would probably not need to archive this much output.
The GEOS-Chem specialty simulations—simulations for species with first-order loss by prescribed oxidant fields (i.e. Hg, CH4, CO2, CO)—will produce much less output than the benchmark simulations. This is because these simulations typically only have a few species.
Reducing output file sizes
In GEOS-Chem 12.6.0 (released 18 Oct 2019), we introduced the capability of horizontal and vertical subsetting for diagnostics being archived to netCDF output. This will let you save only a sub-region of the globe, or a subset of vertical levels (or both) in case you do not wish to archive diagnostics for the entire globe. This can help to further reduce the amount of diagnostic output being sent to disk.
Furthermore, in GEOS-Chem 13.0.0, we have modified the diagnostic code so that diagnostic arrays are only dimensioned with enough elements necessary to save out the required output. For example, if you only wish to output the SpeciesConc_O3 diagnostic, GEOS-Chem will dimension the relevant array with (NX,NY,NZ,1) elements (1 because we are only archiving 1 species). This can drastically reduce the amount of memory that your simulation wil require.
Archiving hourly or daily timeseries output would require much more disk space than the monthly-mean output. The disk space actually used will depend on how many quantities are archived and what the archival frequency is.