Calculates the latent heat flux using the Priestley-Taylor method. Positive heat flux signifies flux away from the surface, negative values signify flux towards the surface.
Usage
latent_priestley_taylor(...)
# Default S3 method
latent_priestley_taylor(temp, rad_bal, soil_flux, surface_type, ...)
# S3 method for class 'weather_station'
latent_priestley_taylor(weather_station, ...)Arguments
- ...
Additional arguments.
- temp
Air temperature in degrees C.
- rad_bal
Radiation balance in W m-2.
- soil_flux
Soil flux in W m-2.
- surface_type
Surface type, for which a Priestley-Taylor coefficient will be selected. Options: field, bare soil, coniferous forest, water, wetland, spruce forest
- weather_station
Object of class weather_station
Details
The latent heat flux (\(Q_e\)) using the Priestley-Taylor method is calculated as: $$Q_e = \alpha_{PT} \cdot \frac{\Delta}{\Delta + \gamma} \cdot (R_n - G)$$ where: \(\alpha_{PT}\) is the Priestley-Taylor coefficient, \(\Delta\) is the slope of the saturation vapor pressure curve, \(\gamma\) is the psychrometric constant, \(R_n\) is the net radiation, and \(G\) is the soil heat flux.
The Priestley-Taylor coefficient depends on the surface type and is selected
from the internal priestley_taylor_coefficient table. These
surface-specific alpha values are package parameters; the method background
follows Priestley-Taylor as presented in Foken (2016). The helpers
sc() and gam() are Foken/Stull table-scale coefficients used
together in the ratio \(\Delta / (\Delta + \gamma)\).