windkit.create_gewc#

windkit.create_gewc(output_locs, years=None, n_sectors=12, seed=9876538, location_range=(20.0, 25.0), scale_range=(1.2, 2.5), prevailing_direction=270.0, directional_contrast=0.35)[source]#

Create a synthetic generalized extreme wind climate.

“Generalized” means 10 m above a homogeneous surface of roughness 0.05 m - the condition LINCOM downscales from, and pywasp.lincom.v50_lut’s DEFAULT_HGT and DEFAULT_Z0.

The annual maxima are drawn per point and sector from a Gumbel distribution, with the location and scale reduced away from the prevailing direction so that the wind rose is not flat. Directions fall inside their own sector bin. Because the generalized condition is fixed at 10 m, points at the same horizontal location receive the same climate at every height. The repetition is deliberate and permitted by the "optional" height policy of the maxima: LINCOM consumes a generalized climate on the three-dimensional structure of its output points.

Parameters:

  • output_locs (xarray.Dataset) – Output geospatial information.

  • years (array_like or None) – Years to generate. If None, 1979 through 2010 is used, the CFSR period the defaults follow.

  • n_sectors (int) – Number of direction sectors, defaults to 12.

  • seed (int) – Seed for the random data, defaults to 9876538.

  • location_range (tuple of float) – Bounds of the per-point Gumbel location parameter [m s-1]. Defaults to (20.0, 25.0), below the local defaults because the terrain downscaling amplifies these values.

  • scale_range (tuple of float) – Bounds of the per-point Gumbel scale parameter [m s-1]. Defaults to (1.2, 2.5).

  • prevailing_direction (float) – Direction of the strongest sector [degrees]. Defaults to 270.

  • directional_contrast (float) – Fractional reduction of the maxima in the sector opposite the prevailing one. Defaults to 0.35.

Returns:

ds – Generalized extreme wind climate with max_wspd and max_wdir over (sector, year, <space>).

Return type:

xarray.Dataset

Raises:

ValueError – If years is not a one-dimensional sequence containing at least two entries.

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