isothermal.Rn {bigleaf}

Isothermal Net Radiation

Description

Calculates the isothermal net radiation, i.e. the net radiation that the surface would receive if it had the same temperature than the air.

Usage

isothermal.Rn(
  data,
  Rn = "Rn",
  Tair = "Tair",
  Tsurf = "Tsurf",
  emissivity,
  constants = bigleaf.constants()
)

Arguments

data

Data.frame or matrix containing all required variables

Rn

Net radiation (W m-2)

Tair

Air temperature (degC)

Tsurf

Surface temperature (degC)

emissivity

Emissivity of the surface (-)

constants

sigma - Stefan-Boltzmann constant (W m-2 K-4)
Kelvin - conversion degree Celsius to Kelvin

Details

The isothermal net radiation (Rni) is given by:

Rni = Rn + \epsilon * \sigma * (Tsurf^4 - Tair^4)

where \epsilon is the emissivity of the surface. Tsurf and Tair are in Kelvin.

Value

Rni -

isothermal net radiation (W m-2)

References

Jones, H. 2014: Plants and Microclimate. 3rd edition, Cambridge University Press.

Examples

# calculate isothermal net radiation of a surface that is 2degC warmer than the air.
isothermal.Rn(Rn=400,Tair=25,Tsurf=27,emissivity=0.98)