| Ld {Thermimage} | R Documentation |
Estimates downward facing longwave radiation (W/m2)
Description
Estimates downward incoming longwave radiation (W/m2) using relationship derived from Konzelmann et al. 1994.
Usage
Ld(Ta = 20, RH = 0.5, n = 0.5)
Arguments
Ta |
Local air temperature (degrees Celsius), ~ 2 m above ground |
RH |
Local relative humidity (fractional value from 0 to 1) |
n |
Fractional cloud cover (fractional value from 0 to 1) |
Details
By estimating the sky emissivity, from information on humidity and cloud cover, the incoming infrared radiation can be estimated using the Stephan-Boltzmann relationship: emissivity*Stephan Boltzmann constant * T^4. The effective atmospheric emissivity is determined from known cloud emissivity (0.97) and empirically determined clear sky emissivities.
Value
A value, vector of length one, corresponding to the incoming longwave radiation, units: W/m2.
Author(s)
Glenn J Tattersall
References
Konzelmann et al 1994. Parameterization of global and longwave incoming radiation for the Greenland ice-sheet. Global and Planetary Change. 9: 143-164.
See Also
Examples
# Returns a value in W/m2 of the estimated incoming longwave radiation
# Example calculation:
Ta<-30
RH<-0.5
n<-0
Ld(Ta, RH, n)