netsse.analys.buoy.spread_dist_params2Fourier

netsse.analys.buoy.spread_dist_params2Fourier(alpha, sigma, gamma, delta, unit='rad')

Infers the Fourier coefficients from the parameters of the directional spreading distribution function, as per Kuik et al. (1988).

Parameters:

• alpha (array_like of shape (Nf,)) – Wave direction [rad, or deg].

• sigma (array_like of shape (Nf,)) – Directional spread [rad, or deg].

• gamma (array_like of shape (Nf,)) – Skewness of the directional distribution [-].

• delta (array_like of shape (Nf,)) – Kurtosis of the directional distribution [-].

• unit ({'rad','deg'}, optional) – Unit of the wave direction and directional spread: 'deg' or 'rad' (default).

Returns:

a1, b1, a2, b2 – First four Fourier coefficients of the directional wave spectrum.

Return type:

array_like of shape (Nf,)

See also

Fourier2spread_dist_params

Infers the parameters of the directional spreading distribution function from the Fourier coefficients.

Shannon_MEMII_Newton

Reconstructs the directional spreading function based on the first four Fourier coefficients of a directional wave spectrum.

References

Kuik, A. J., van Vledder, G. P., & Holthuijsen, L. H. (1988). A Method for the Routine Analysis of Pitch-and-Roll Buoy Wave Data. Journal of Physical Oceanography, 18(7), 1020–1034.

Example

>>> [a1,b1,a2,b2] = spread_dist_params2Fourier(alpha,sigma,gamma,delta,unit)