windspharm is a Python package for computing quantities derived from global wind fields using spherical harmonics, licensed under the MIT license.

windspharm provides a user-friendly interface for vector wind computations on the sphere (e.g., divergence, streamfunction etc.). windspharm is based on the pyspharm module.

windspharm provides a replacement for the windfield package from CDAT (windfield was based on the sphere module, which is now deprecated).

windspharm only requires numpy and pyspharm, but for full functionality (meta-data interfaces) either the iris module or the cdms2 module is required. cdms2 is part of the Climate Data Analysis Tools (CDAT) or can be obtained separately in the cdat_lite package.

Documentation is available online. The package docstrings are also very complete and can be used as a source of reference when working interactively.

• Do I need CDAT/cdms2 or iris to use windspharm? No. All the computation code uses numpy only. The iris or cdms2 modules are only required for the meta-data preserving interfaces.
• Is windspharm a drop in replacement for windfield? No. Because windspharm was written from scratch the naming conventions for methods are different. Some new methods have been added compared to windfield, and some methods from windfield do not exist in windspharm.

sudo python setup.py install

to install system-wide, or to install in your home directory:

python setup.py install --user