Gb.Thom: Boundary Layer Conductance according to Thom 1972

In bigleaf: Physical and Physiological Ecosystem Properties from Eddy Covariance Data

Boundary Layer Conductance according to Thom 1972

Description

An empirical formulation for the canopy boundary layer conductance for heat transfer based on a simple ustar dependency.

Usage

Gb.Thom(ustar, Sc = NULL, Sc_name = NULL, constants = bigleaf.constants())

Arguments

ustar	Friction velocity (m s-1)
Sc	Optional: Schmidt number of additional quantities to be calculated
Sc_name	Optional: Name of the additional quantities, has to be of same length than Sc_name
constants	k - von-Karman constant Sc_CO2 - Schmidt number for CO2 Pr - Prandtl number (if Sc is provided)

Details

The empirical equation for Rb suggested by Thom 1972 is:

Rb = 6.2ustar^-0.67

Gb (=1/Rb) for water vapor and heat are assumed to be equal in this package. Gb for other quantities x is calculated as (Hicks et al. 1987):

Gb_x = Gb / (Sc_x / Pr)^0.67

where Sc_x is the Schmidt number of quantity x, and Pr is the Prandtl number (0.71).

Value

a data.frame with the following columns:

Gb_h	Boundary layer conductance for heat transfer (m s-1)
Rb_h	Boundary layer resistance for heat transfer (s m-1)
kB_h	kB-1 parameter for heat transfer
Gb_Sc_name	Boundary layer conductance for Sc_name (m s-1). Only added if Sc_name and Sc_name are provided

References

Thom, A., 1972: Momentum, mass and heat exchange of vegetation. Quarterly Journal of the Royal Meteorological Society 98, 124-134.

Hicks, B.B., Baldocchi, D.D., Meyers, T.P., Hosker, J.R., Matt, D.R., 1987: A preliminary multiple resistance routine for deriving dry deposition velocities from measured quantities. Water, Air, and Soil Pollution 36, 311-330.

See Also

Gb.Choudhury, Gb.Su, aerodynamic.conductance

Examples

Gb.Thom(seq(0.1,1.4,0.1))

## calculate Gb for SO2 as well
Gb.Thom(seq(0.1,1.4,0.1),Sc=1.25,Sc_name="SO2")

bigleaf documentation built on Aug. 22, 2022, 9:09 a.m.