improver.cli.phase_probability module

Interface to precip_phase_probability.

process(*cubes)[source]

Converts a phase-change-level cube into the probability of a specific precipitation phase being found at the surface or at a site’s altitude.

If provided with a phase-change level cube without a percentile coordinate, the phase-change level is compared directly to the orographic / site height for each grid cell / site. A binary probability of the phase is returned for each grid cell / site.

If the phase-change level cube has a percentile coordinate specific percentiles will be used for the snow, rain or hail falling-levels. If a snow-falling-level diagnostic is provided, the 80th percentile altitude will be used. If a rain-falling-level or hail-falling-level diagnostic is provided, the 20th percentile altitude will be used.

Parameters:

cubes (iris.cube.CubeList or list) –

Contains cubes of the altitude of the phase-change level (this can be snow->sleet, hail->rain or sleet->rain), and the altitude of the orography at grid cells, or the altitude of sites at which the phase probability should be returned.

The name of the phase-change level cube must be either:

  • ”altitude_of_snow_falling_level”

  • ”altitude_of_rain_from_hail_falling_level”

  • ”altitude_of_rain_falling_level”

If the phase-change level cube contains percentiles, these must include the 80th percentile for the snow-falling-level, and the 20th percentile for any other phase.

The name of the orography cube must be “surface_altitude”. The name of the site ancillary most be “grid_neighbours”.