constant PV f-plane QG turbulence (a.k.a surface QG turbulence).

Doubly periodic geometry with sin(2*pi/L) jet basic state.

References:

• http://journals.ametsoc.org/doi/pdf/10.1175/2008JAS2921.1 (section 3)
• http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281978%29035%3C0774%3AUPVFPI%3E2.0.CO%3B2

includes Ekman damping, linear thermal relaxation back to equilibrium jet, and hyperdiffusion.

pv has units of meters per second. scale by f*theta0/g to convert to temperature.

FFT spectral collocation method with 4th order Runge Kutta time stepping (dealiasing with 2/3 rule, hyperdiffusion treated implicitly).

Requires numpy (pyfftw, netcdf4-python and matplotlib highly recommended).

example code to run model and animate the solution in sqg_run.py

To run EnKF data assimilation:

• install with python setup.py install.
• first run sqg_run.py to generate nature run.
• then run sqg_enkf.py.