Instructions for installing SUMMA on Mac OS X

The following has been tested on a MacBook Pro and iMac, both using OS X v. 10.12.6 (Sierra) and with MacPorts as the OS X package manager. It should also work on older versions of OS X or with other package managers such as fink or homebrew, but you will undoubtedly need to make some modifications.

This document is mainly for people who want to use SUMMA in their modeling project, rather than contribute or change the SUMMA source code. If you want to contribute to SUMMA, , please see the following documents:

In the following I will assume that you don't have a Fortran compiler or NetCDF installed. If you do, just scroll down.

  1. Install MacPorts. This is a package manager for OS X (Darwin), which will let you install many software packages that are typically used in a Unix-like environment (which is what your Mac provides). MacPorts has detailed instructions on how it should be installed for various versions of OS X. Just follow the instructions (you will be asked to install Xcode, etcetera). If you know nothing about Unix/Linux/Darwin, now is the time to learn.

  2. Open a terminal (Applications --> Utilities -->

  3. Use MacPorts to install NetCDF by typing the following on the command-line

    sudo port install netcdf

    You will be asked to provide your password. Note that you can only sudo (execute a command as a superuser) if you have administrative privileges for your machine (i.e., you can install software, etc.). If you do not have administrative privileges, talk to the person who maintains your computer. A whole bunch of other packages (dependencies) will be installed as well. Just let MacPorts do its work, this is why you are using a package manager. It may take a while the first time you do this. Make sure that the NetCDF is compiled using gcc6 or higher. You can specify different variants of the package to be installed. See the MacPorts documentation for details.

  4. Install the Fortran version of the NetCDF library

    sudo port install netcdf-fortran

    Note what version of gcc was used to compile the NetCDF Fortran library. If you did not see it, type

    sudo port info netcdf-fortran

    The gcc compiler will be listed under Build Dependencies. For example, gcc6, which is what I'll assume for now. However, make sure to use the correct version of gcc (i.e. the one used to compile the netcdf-fortran library) when you compile SUMMA.

  5. Install the correct version of gcc (here we'll assume gcc6)

    sudo port install gcc6

  6. Note that MacPorts typically installs everything in the /opt/local directory. Make sure you now have NetCDF and gfortran installed:

    ls /opt/local/lib/*netcdf*

    You should have one or more libnetcdf.* (C-version of NetCDF library) and libnetcdff.* (Fortran version of NetCDF library) files

    ls /opt/local/bin/*fortran*

    You should have one or more gfortran-* files. If you installed gcc6, the gfortran executable will be /opt/local/bin/gfortran-mp-6. Since MacPorts will have modified your path so that /opt/local/bin is part of that, you should be able to invoke the compiler by typing


    and the results should be

    gfortran-mp-6: fatal error: no input files compilation terminated.

    Note that you may also have a symbolic link named /opt/local/bin/gfortran. Make sure that that link points to the correct executable (e.g. /opt/local/bin/gfortran-mp-6). If so, then you should be able to invoke the correct version of the fortran compile by simply typing gfortran.

  7. While you are at it, there are a number of other packages that would be useful to install, in particular

    • sudo port install ncview : to visualize NetCDF files
    • sudo port install nco : to manipulate NetCDF files, see the NCO homepage
    • sudo port install cdo : to manipulate NetCDF files, see the CDO homepage
  8. Now obtain the SUMMA source code from the SUMMA source code repository. You may just want to download the latest tagged release. Unless you are planning to contribute to the source code, there is no need to clone or fork the repository.

  9. Untar or unzip the archive, then go to the summa/build directory and follow the instructions in the SUMMA installation page. If you are using MacPorts, the FC_ENV can be set to gfortran-6-macports.