CliMT: Climate Modeling Toolkit


CliMT is a Python-based software component toolkit that allows users to build and run climate models in a fairly painless manner. Think of CliMT as a Lego set, where each brick is a climate model component such as a radiation or convection scheme. Each component is coded in Fortran or C, but the user need never deal with the compiled code directly: CliMT makes these components accessible at the Python level, where they can be easily combined into customized climate models. If you're unfamiliar with these issues, here is some further discussion.

CliMT is in its infancy: a radiative-convective column model is about the most complex construct you can build at present. One day, CliMT will grow up and allow you to build a full 3-D parallel climate model.

CliMT is aimed at a broad audience. Because the accent is on simplicity and intuitiveness, it should be accessible to undergraduate or even high-school students. On the other hand, it uses state-of-the-art components, and so is suitable for full-blown research projects.


To install and run CliMT, you need

  • A working Python installation (2.2 or higher).
  • The Numeric Python module.
  • A C compiler (GNU gcc is fine).
  • A Fortran90 compiler. Currently, supported systems are:
    • Linux w/ PGI pgf90 or Intel ifc
    • Mac OSX w/ IBM xlf
    It shouldn't be too hard to compile CliMT on other Unix platform/compiler combinations - just edit CliMT/src/ to add the new flags. If you manage to do this, please let me know! (
  • A minimum of familiarity with Python.

Download and installation

The most recent version is available here.

To install:

  • tar xvzf climt.tar.gz
  • cd CliMT/src
  • edit the section marked "User adjustable parameters" near the top of Makefile, set the correct values for your system
  • make

If compilation was successful, make sure the CliMT install location (CLIMT_DIR in the Makefile) is on your Python executable path (you can also set environment variable PYTHONPATH to point to wherever you chose for CLIMT_DIR). Then try make test; this should produce a bunch of reasonable-looking numbers and no error messages. If you encounter problems you can't solve, please email me <> and we'll work on it.

Using CliMT

Using CliMT consists of writing a Python script which invokes the components necessary for a given application. Here is a simple example. You'll find more in lib/examples.

Python is also a good language for CGI scripting, so you can easily build web interfaces to CliMT applications. Here is an example of CliMT used in a CGI script.


This is bare-bones for now; more on the way soon.

Module Name Pydoc Key Depend Function
const HTML Y None Holds relevant physical constants
thermodyn HTML Y None Provides accurate thermodynamic functions
mathutil HTML Y None Mathematical utility functions
radiation HTML Y None Provides access to radiative schemes
convection HTML Y None Provides access to convection schemes


CliMT is a project of the Climate Systems Center at the Department of the Geophysical Sciences, University of Chicago. It is funded by NSF Information Technology Research grant ATM-0121028. Key developers are Rodrigo Caballero and Mike Steder.

Valid HTML 4.01! Valid CSS! Updated: March 28, 2004 by Rodrigo Caballero <>.