improver.cli.estimate_dz_rescaling module
CLI to estimate a scaling factor to account for a correction linked to the difference in altitude between the grid point and the site location.
- process(forecast, truth, neighbour_cube, *, forecast_period, dz_lower_bound=None, dz_upper_bound=None, land_constraint=False, similar_altitude=False, site_id_coord='wmo_id')[source]
Estimate a scaling factor to account for a correction linked to the difference in altitude between the grid point and the site location. Note that the output will have the same sites as provided by the neighbour cube.
- Parameters:
forecast (iris.cube.Cube) – Historical percentile forecasts. A 50th percentile forecast is required.
truth (iris.cube.Cube) – Truths that are expected to match the validity times of the forecasts.
neighbour_cube (iris.cube.Cube) – The neighbour cube is a cube of spot-data neighbours and the spot site information.
forecast_period (int) – The forecast period in hours that is considered representative of the input forecasts. This is required as the input forecasts could contain multiple forecast periods.
dz_lower_bound (float) – The lowest acceptable value for the difference in altitude between the grid point and the site. Sites with a lower (or more negative) difference in altitude will be excluded. If the altitude difference is calculated as site altitude minus the grid point altitude, the lower bound therefore indicates how far below the orographic surface (i.e. within unresolved valleys) the correction should be applied. Defaults to None.
dz_upper_bound (float) – The highest acceptable value for the difference in altitude between the grid point and the site. Sites with a larger positive difference in altitude will be excluded. If the altitude difference is calculated as site altitude minus the grid point altitude, the upper bound therefore indicates how far above the orographic surface (i.e. on unresolved hills or mountains) the correction should be applied. Defaults to None.
land_constraint (bool) – Use to select the nearest-with-land-constraint neighbour-selection method from the neighbour_cube. This means that the grid points should be land points except for sites where none were found within the search radius when the neighbour cube was created. May be used with similar_altitude.
similar_altitude (bool) – Use to select the nearest-with-height-constraint neighbour-selection method from the neighbour_cube. These are grid points that were found to be the closest in altitude to the spot site within the search radius defined when the neighbour cube was created. May be used with land_constraint.
site_id_coord (str) – The name of the site ID coordinate. This defaults to ‘wmo_id’.
- Returns:
Cube containing a scaling factor computed using the difference in altitude between the grid point and the site location.
- Return type: