Ld: Estimates downward facing longwave radiation (W/m2)

Description Usage Arguments Details Value Author(s) References See Also Examples

View source: R/Ld.R

Description

Estimates downward incoming longwave radiation (W/m2) using relationship derived from Konzelmann et al. 1994.

Usage

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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

Lw

Examples

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# 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)

Thermimage documentation built on May 29, 2017, 6:47 p.m.