radiometric.surface.temp {bigleaf}

Radiometric Surface Temperature

Description

Radiometric surface temperature from longwave radiation measurements.

Usage

radiometric.surface.temp(
  data,
  LW_up = "LW_up",
  LW_down = "LW_down",
  emissivity,
  constants = bigleaf.constants()
)

Arguments

data

Data.frame or matrix containing all required input variables

LW_up

Longwave upward radiation (W m-2)

LW_down

Longwave downward radiation (W m-2)

emissivity

Emissivity of the surface (-)

constants

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

Details

Radiometric surface temperature (Trad) is calculated as:

Trad = ((LW_up - (1 - \epsilon)*LW_down) / (\sigma \epsilon))^(1/4)

Value

a data.frame with the following columns:

Trad_K

Radiometric surface temperature (K)

Trad_degC

Radiometric surface temperature (degC)

References

Wang, W., Liang, S., Meyers, T. 2008: Validating MODIS land surface temperature products using long-term nighttime ground measurements. Remote Sensing of Environment 112, 623-635.

Examples

# determine radiometric surface temperature for the site DE-Tha in June 2014 
# assuming an emissivity of 0.98.
# (Note that variable 'LW_down' was only included for the DE-Tha example dataset
# and not for the others due restrictions on file size) 
Trad <- radiometric.surface.temp(DE_Tha_Jun_2014,emissivity=0.98)
summary(Trad)