waq

waq(lon, lat, q, sigma=None, omega=None, flip=True, skip=10)[source]

Return the finite-amplitude wave activity. See [NZ10] for details.

Parameters

  • lon, lat (ndarray) – The longitude and latitude coordinates.

  • q (ndarray) – The potential vorcitiy data. Should be sorted lon x lat x … (this will be changed in a future version).

  • skip (int, optional) – The interval of sorted q from which we select output Q values.

  • flip (bool, optional) – Whether to flip the input data along the latitude dimension. Use this if your zonal average gradient is negative poleward.

  • omega (ndarray, optional) – The vertical wind. Shape must match q.

  • sigma (ndarray, optional) – The data weights, useful for isentropic coordinates. Shape must match q.

References

NZ10

Noboru Nakamura and Da Zhu. Finite-Amplitude Wave Activity and Diffusive Flux of Potential Vorticity in Eddy–Mean Flow Interaction. Journal of the Atmospheric Sciences, 67(9):2701–2716, April 2010. doi:10.1175/2010JAS3432.1.