CLASS: Chemistry Land-surface Atmosphere Soil Slab model

Download CLASS

CLASS is released under a GPLv3 licence, the source code (with licence) is available at this website. Pre-compiled executables for Windows and OS X are available, for compiling CLASS on Linux see "useful links".

Executables Source

Suggestions / bugs

We have designed CLASS with care, but in case you run in to problems, please report them to us and we will do our best to solve issue.

Bugtracker Email

Instruction and knowledge clips

To help users get started, we created short instruction and knowledge clips which introduce the CLASS model, the different options and settings, and some of the theory behind the model.

View the clips

Useful links

Below you can find some additional information on how to compile the model, and run it on recent versions of OS X.

Compiling CLASS on Linux »

Notes for OS X users »

Research versions CLASS

Two research codes are available for conducting advanced experiments. The first is the MXLCH Fortran code, which contains all the features (and some extras) of the graphical user interface. The second is the Python version, which is a basic implementation of the coupled land-atmosphere model without the chemistry.

The research codes have been used in a number of publication. Click here for an overview.

Fortran Python


Our book: Atmospheric boundary layer: Integrating chemistry and land interactions is published by Cambridge University Press!

Cambridge website

The book has been reviewed by Katul and Fuentes (2016, Boundary-Layer Meteorology) and Schultz (2016, Agricultural and Forest Meteorology).


We provide the numerical settings of the hands-on exercises proposed in the book. The book describes all exercises in detail, including background information on the initial and boundary conditions.

Exercises Answers