Skip to content
Switch branches/tags

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time

CLASS model

CLASS: Chemistry Land-surface Atmosphere Soil Slab model


CLASS is part of a book (soon to be) published at Cambridge University Press: "Atmospheric boundary layer: Integrating chemistry and land interactions" by Jordi Vila-Guerau de Arellano, Chiel C. van Heerwaarden, Bart J.H. van Stratum and Kees van den Dries.

Obtaining the CLASS software

CLASS can be downloaded as precompiled binaries for Windows and OS X.

For information on compiling CLASS on Linux / OS X, see the notes below.

Note for OS X users

On recent versions of OS X, opening CLASS for the first time will result in a warning: "CLASS can’t be opened because it is from an unidentified developer". To circumvent this problem, right click the application and select "open" and again "open" in the dialog instead of double clicking the application. This step is only needed once.


Bugs can be reported at

In order to reproduce and fix the bug, we will most likely need:

  • Information on the operating system you are using (Windows or OS X version, Linux distribution)
  • The git-hash, shown in the 'about CLASS' window (e.g. git-hash: v1.0_beta2-6-g49b7603)
  • A description of the exact steps needed to reproduce the problem.

Compiling CLASS

The source code of CLASS can be downloaded manually from GitHub or (preferably) using GIT:

git clone

Both methods will always provide you the most recent (stable) version of CLASS. There are two ways of compiling CLASS: using QtCreator or using the command line.


After installing QtCreator, open the CLASS project file ( in QtCreator and select "build" > "run". This should compile and start CLASS.

Command line

Without QtCreator installed, some additional packages are needed, e.g.

  • Ubuntu (10.04.2 LTS): g++ qt4-qmake libqt4-dev
  • OpenSUSE (11.4): libqt4-devel make

After installing the required packages, calling:


from the source directory of CLASS should compile the model.

In order to build the code on OS X without creating an Xcode project, call:

qmake -spec macx-g++