Brian Rose, University at Albany

This is a stand-alone Python wrapper for the NCAR CAM3 radiation scheme.

The primary use-case is to serve as the under-the-hood radiation driver for climlab, but it can be used as a stand-alone model if you are familiar with the Fortran source code. This is a lightweight wrapper that emulates the Fortran interface as closely as possible.

Pre-built binaries for many platforms are available from conda-forge.

To install in the current environment:

conda install climlab-cam3-radiation --channel conda-forge

or create a self-contained environment:

conda create --name my_env python=3.12 climlab-cam3-radiation --channel conda-forge
conda activate my_env

See below for instructions on how to build from source.

You can import the Fortran driver into a Python session with

import climlab_cam3_radiation as cam3

Please see the directory climlab_cam3_radiation/tests/ directory in this repository for working examples that set up all the necessary input arrays and call the driver.

Here are instructions to create a build environment (including Fortran compiler) with conda and build using f2py.

To build:

conda env create --file ./ci/requirements-macos-arm64.yml
conda activate cam3_build_env
python -m pip install . --no-deps -vv

To run tests, do this from any directory other than the climlab-cam3-radiation repo:

pytest -v --pyargs climlab_cam3_radiation

• Version 0.3.1 (February 2025) modernizes the build system for this package can run on Python 3.12 and above. The build now uses meson. This version also uses gridpoint-specific values of the input parameter eccf (solar irradiance factor), consistent with recent changes in climlab-rrtmg.
• Version 0.2 is the first public release (April 2022). The Python wrapper code has been extracted from climlab v0.7.13.