speedy.f90 is an intermediate complexity atmospheric general circulation model written in modern Fortran. It is based on SPEEDY, developed by Fred Kucharski, Franco Molteni and Martin P. King.

speedy.f90 has only one dependency: the NetCDF library. To build speedy.f90:

1. Install the NetCDF library and locate the install directory. For example, on my system it is stored in /usr.
2. Set the NETCDF environment variable to point to the directory containing the NetCDF include and lib directories. For example, for my system I run export NETCDF=/usr.
3. Run build.sh to build speedy.f90: bash build.sh. A binary directory, bin, will be created an the speedy.f90 executable speedy will be placed in this directory.
4. Run run.sh to run speedy.f90: bash run.sh. The output will be stored in rundir. By default, speedy.f90 will run for two days and output one NetCDF file for each time step.

Cite the Zenodo DOI given above directly, as well as the following three model description and verification papers based on the original SPEEDY model:

• Molteni, F., Atmospheric simulations using a GCM with simplified physical parametrizations. I: model climatology and variability in multi-decadal experiments. Climate Dynamics 20, 175–191 (2003). https://doi.org/10.1007/s00382-002-0268-2
• Kucharski, F., Molteni, F. & Bracco, A. Decadal interactions between the western tropical Pacific and the North Atlantic Oscillation. Climate Dynamics 26, 79–91 (2006). https://doi.org/10.1007/s00382-005-0085-5
• Kucharski, F., Molteni, F., King, M. P., Farneti, R., Kang, I., & Feudale, L., On the Need of Intermediate Complexity General Circulation Models: A “SPEEDY” Example. Bulletin of the American Meteorological Society, 94(1), 25-30 (2013). https://doi.org/10.1175/BAMS-D-11-00238.1