Global Spectral Barotropic Model Forecasts
Global Vort. and Wind | N. Amer. Hgt and Wind
Written by Luke Madaus (4/2011) to prove to himself that he knew enough to do it.
Code available on GitHub: https://github.com/lmadaus/Barotropic-Python
Based loosely on the Held-Suarez Barotropic Model, though without a lot of the finer details.
Model code is written in Python and utilizes Jeff Whittaker's Pyspharm module to easily do the spherical harmonic transforms.
Initialization is off of the computed non-divergent component of the 500mb winds from the NCEP reanalysis (explains the 3-day delay, but the files are nicely in netCDF format...)
This data is on a 2.5x2.5 degree grid and the resulting truncation is T72.
Model integrates with a timestep of 1800s with leapfrog timestepping and Robert filter applied to previous time steps to help dampen craziness.