improver.cli.nbhood module

Script to run neighbourhood processing.

process(cube, mask=None, *, neighbourhood_output, neighbourhood_shape='square', radii, lead_times=None, degrees_as_complex=False, weighted_mode=False, area_sum=False, percentiles=(0, 5, 10, 20, 25, 30, 40, 50, 60, 70, 75, 80, 90, 95, 100), halo_radius=None)[source]

Runs neighbourhood processing.

Apply the requested neighbourhood method via the NeighbourhoodProcessing plugin to a Cube.

Parameters:

  • cube (iris.cube.Cube) – The Cube to be processed, usually a thresholded data set.

  • mask (iris.cube.Cube) – A cube to mask the input cube. The data should contain 1 for usable points and 0 for discarded points. Can’t be used with “percentiles” as neighbourhood_output (Optional)

  • neighbourhood_output (str) – The form of the results generated using neighbourhood processing. If “probabilities” is selected, the mean probability with a neighbourhood is calculated. If “percentiles” is selected, then the percentiles are calculated with a neighbourhood. Calculating percentiles from a neighbourhood is only supported for a circular neighbourhood, and the input cube should be ensemble realizations. The calculation of percentiles from a neighbourhood is notably slower than neighbourhood processing using a thresholded probability field. Options: “probabilities”, “percentiles”.

  • neighbourhood_shape (str) – Name of the neighbourhood method to use. Only a “circular” neighbourhood shape is applicable for calculating “percentiles” output. Options: “circular”, “square”. Default: “square”.

  • radii (list of float) – The radius or a list of radii in metres of the neighbourhood to apply. If it is a list, it must be the same length as lead_times, which defines at which lead time to use which nbhood radius. The radius will be interpolated for intermediate lead times.

  • lead_times (list of int) – The lead times in hours that correspond to the radii to be used. If lead_times are set, radii must be a list the same length as lead_times.

  • degrees_as_complex (bool) – Include this option to process angles as complex numbers. Not compatible with circular kernel or percentiles.

  • weighted_mode (bool) – Include this option to set the weighting to decrease with radius. Otherwise a constant weighting is assumed. weighted_mode is only applicable for calculating “probability” neighbourhood output using the circular kernel.

  • area_sum (bool) – Return sum rather than fraction over the neighbourhood area.

  • percentiles (float) – Calculates value at the specified percentiles from the neighbourhood surrounding each grid point. This argument has no effect if the output is probabilities.

  • halo_radius (float) – Set this radius in metres to define the excess halo to clip. Used where a larger grid was defined than the standard grid and we want to clip the grid back to the standard grid. Otherwise no clipping is applied.

Returns:

A processed Cube.

Return type:

iris.cube.Cube

Raises:

  • RuntimeError – If weighted_mode is used with the wrong neighbourhood_output.

  • RuntimeError – If degree_as_complex is used with neighbourhood_output=’percentiles’.

  • RuntimeError – If degree_as_complex is used with neighbourhood_shape=’circular’.