Hardware requirements

Computer system requirements

Before you can run HEMCO, you will need to have one the following items.




A Unix-based computer system

You will need a Unix operating system environment in order to run HEMCO. Any flavor of Unix (e.g. CentOS, Ubuntu, Fedora, etc.) should work just fine.


An account on the Amazon Web Services cloud

If your institution has computational resources (e.g. a shared computer cluster with many cores, sufficient disk storage and memory), then you can run GEOS-Chem there. Contact your IT staff for assistance.

If your institution lacks computational resources (or if you need additional computational resources beyond what is available), then you should consider signing up for access to the Amazon Web Services cloud. Using the cloud has the following advantages:

  • You can run GEOS-Chem without having to invest in local hardware and maintenance personnel.

  • You won’t have to download any meteorological fields or emissions data. All of the necessary data input for GEOS-Chem will be available on the cloud.

  • You can initialize your computational environment with all of the required software (e.g. compilers, libraries, utilities) that you need for GEOS-Chem.

  • Your GEOS-Chem runs will be 100% reproducible, because you will initialize your computational environment the same way every time.

  • You will avoid GEOS-Chem compilation errors due to library incompatibilities.

  • You will be charged for the computational time that you use, and if you download data off the cloud.

GEOS-Chem 12.0.0 and later versions can be used on the Amazon Web Services cloud computing platform. You can learn more about how to use GEOS-Chem on the cloud by visiting this tutorial (

Memory requirements

If you plan to run GEOS-Chem on a local computer system, please make sure that your system has sufficient memory and disk space:

Software requirements

Supported compilers for HEMCO

The table below lists the supported compilers for HEMCO.

HEMCO is written in the Fortran programming language. However, you will also need C and C++ compilers to install certain libraries (like netCDF) on your system.




Best way to install

`Intel Compiler Suite (icc, icpc, ifort)

The Intel Compiler Suite is our recommended proprietary compiler collection.

Intel compilers produce well-optimized code that runs extremely efficiency on machines with Intel CPUs. Many universities and institutions will have an Intel site license that allows you to use these compilers.

The GCST has tested with these versions (but others may work as well):


  • 18.0.5

  • 17.0.4

  • 15.0.0

  • 13.0.079

  • 11.1.069

Install from Intel (requires purchase of a site license or a student license)

GNU Compiler Collection (gcc, g++, gfortra n)

The GNU Compiler Collection is our recommended open-source compiler collection.

Because the GNU Compiler Collection is free and open source, this is a good choice if your institution lacks an Intel site license, or if you are running GEOS-Chem on the Amazon EC2 cloud environment.

The GCST has tested with these versions (but others may work as well):

  • 10.2.0

  • 9.3.0

  • 9.2.0

  • 8.2.0

  • 7.4.0

  • 7.3.0

  • 7.1.0

  • 6.2.0

Install via Spack

Required software packages for HEMCO



Best way to install

Git (a source code management system)

GEOS-Chem source code can be downloaded using the Git source code management system. GEOS-Chem software repositories are stored at the https:// organization page. Please see our Guide to using Git with GEOS-Chem for more information about how to use Git with GEOS-Chem.

Direct install from


CMake is software that directs how the GEOS-Chem source code is compiled into an executable.

  • CMake is optional for GEOS-Chem versions 12.6.0 through 12.9.3.

  • CMake is REQUIRED for GEOS-Chem versions 13.0.0 and later.

Install with Spack

GNU Make

GNU Make is software that can build executables from source code.

  • NOTE: While GNU Make is not required for GEOS-Chem 13.0.0 and later, some external libraries that you might need to build will require GNU Make. Therefore it is best to download GNU Make along with CMake.

Install with Spack

netCDF and netCDF-Fortran

  • plus dependencies (e.g. HDF5, zlib, etc)

GEOS-Chem input and output data files use the netCDF file format. This is a self-describing file format that allows metadata (descriptive text) to be stored alongside data values. Please see our Guide to netCDF in GEO S-Chem for more information about the netCDF file format and software library.

Install with Spack

Required source code and data for HEMCO



Best way to install

A clone of the geoschem/HEMCO repository repository

The HEMCO (Harmonized Emissions Component codebase.

Git clone from geoschem/HEMCO

The GEOS-Chem shared data directories

This is the directory structure containing the meteorology and emissions data that GEOS-Chem reads as input. For more information, please see our Downloading GEOS-Chem data directories wiki page.

Perform a HEMCO dry run