psychrometric_vapor_pressure_wet¶
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metpy.calc.
psychrometric_vapor_pressure_wet
(dry_bulb_temperature, wet_bulb_temperature, pressure, psychrometer_coefficient=<Quantity(0.000621, '1 / kelvin')>)[source]¶ Calculate the vapor pressure with wet bulb and dry bulb temperatures.
This uses a psychrometric relationship as outlined in [WMO8-2014], with coefficients from [Fan1987].
Parameters: - dry_bulb_temperature (pint.Quantity) – Dry bulb temperature
- wet_bulb_temperature (pint.Quantity) – Wet bulb temperature
- pressure (pint.Quantity) – Total atmospheric pressure
- psychrometer_coefficient (pint.Quantity, optional) – Psychrometer coefficient. Defaults to 6.21e-4 K^-1.
Returns: pint.Quantity – Vapor pressure
Notes
e′=e′w(Tw)−Ap(T−Tw)- e′ is vapor pressure
- e′w(Tw) is the saturation vapor pressure with respect to water at temperature Tw
- p is the pressure of the wet bulb
- T is the temperature of the dry bulb
- Tw is the temperature of the wet bulb
- A is the psychrometer coefficient
Psychrometer coefficient depends on the specific instrument being used and the ventilation of the instrument.
See also