improver.wind_calculations.vertical_updraught module

This module contains the VerticalUpdraught plugin

class VerticalUpdraught(model_id_attr=None)

Bases: BasePlugin

Methods to calculate the maximum vertical updraught from CAPE and precipitation rate as defined in Hand (2002) and Golding (1998) with the precipitation rate modifier found in the UKPP CDP code.

Hand, W. 2002. “The Met Office Convection Diagnosis Scheme.” Meteorological Applications

9(1): 69-83. doi:10.1017/S1350482702001081.

Golding, B.W. 1998. “Nimrod: A system for generating automated very short range forecasts.”

Meteorol. Appl. 5: 1-16. doi:https://doi.org/10.1017/S1350482798000577.

__init__(model_id_attr=None)

Set up class

Parameters:

model_id_attr (Optional[str]) – Name of model ID attribute to be copied from source cubes to output cube

_abc_impl = <_abc_data object>

_input_times_error()

Returns appropriate error message string if :rtype: str

• CAPE cube time is unbounded

• CAPE time point is lower bound of precip cube time point

• CAPE and precip cubes have different forecast reference times

_make_updraught_cube(data)

Puts the data array into a CF-compliant cube

Return type:

Cube

_parse_inputs(inputs)

Separates input CubeList into CAPE and precipitation rate objects with standard units and raises Exceptions if it can’t, or finds excess data.

Parameters:

inputs (List[Cube]) – List of Cubes containing exactly one of CAPE and Precipitation rate.

Raises:

ValueError – If additional cubes are found

Return type:

None

_updraught_from_cape()

Calculate the updraught from CAPE data

Calculation is 0.25 * sqrt(2 * cape)

Returns zero where CAPE < 10 J kg-1

Return type:

ndarray

_updraught_increment_from_precip()

Calculate the updraught increment from the precipitation rate.

Calculation is 7.33 * (precip / 28.7)^0.22 Where precipitation rate < 5 mm h-1, increment is zero.

Return type:

ndarray

process(inputs)

Executes methods to calculate updraught from CAPE and precipitation rate and packages this as a Cube with appropriate metadata.

Parameters:

inputs (List[Cube]) – List of CAPE and precipitation rate cubes (any order)

Returns:

Containing maximum vertical updraught

Return type:

Cube