improver.generate_ancillaries.generate_svp_table module

A module for creating a saturated vapour pressure table

class SaturatedVapourPressureTable(t_min=183.15, t_max=338.25, t_increment=0.1)[source]

Bases: BasePlugin

Plugin to create a saturated vapour pressure lookup table.

MAX_VALID_TEMPERATURE = 373.0

MIN_VALID_TEMPERATURE = 173.0

__init__(t_min=183.15, t_max=338.25, t_increment=0.1)[source]

Create a table of saturated vapour pressures that can be interpolated through to obtain an SVP value for any temperature within the range t_min –> (t_max - t_increment).

The default min/max values create a table that provides SVP values covering the temperature range -90C to +65.1C. Note that the last bin is not used, so the SVP value corresponding to +65C is the highest that will be used.

Parameters:

t_min (float) – The minimum temperature for the range, in Kelvin.
t_max (float) – The maximum temperature for the range, in Kelvin.
t_increment (float) – The temperature increment at which to create values for the saturated vapour pressure between t_min and t_max.

_abc_impl = <_abc_data object>

process()[source]

Create a lookup table of saturation vapour pressure in a pure water vapour system for the range of required temperatures.

Return type:: Cube
Returns:: A cube of saturated vapour pressure values at temperature points defined by t_min, t_max, and t_increment (defined above).

saturation_vapour_pressure_goff_gratch(temperature)[source]

Saturation Vapour pressure in a water vapour system calculated using the Goff-Gratch Equation (WMO standard method).

Parameters:: temperature (ndarray) – Temperature values in Kelvin. Valid from 173K to 373K
Return type:: ndarray
Returns:: Corresponding values of saturation vapour pressure for a pure water vapour system, in hPa.

References

Numerical data and functional relationships in science and technology. New series. Group V. Volume 4. Meteorology. Subvolume b. Physical and chemical properties of the air, P35.