Estimate net radiation balance expressed as a flux in W/m2. If
lw.down.irradiance
is passed a value in W / m2 the difference is
computed directly and if not an approximate value is estimated, using
R_rel = 0.75
which corresponds to clear sky, i.e., uncorrected for
cloudiness. This is the approach to estimation is that recommended by FAO for
hourly estimates while here we use it for instantaneous or mean flux rates.
Usage
net_irradiance(
temperature,
sw.down.irradiance,
lw.down.irradiance = NULL,
sw.albedo = 0.23,
lw.emissivity = 0.98,
water.vp = 0,
R_rel = 1
)
Arguments
- temperature
numeric vector of air temperatures (C) at 2 m height.
- sw.down.irradiance, lw.down.irradiance
numeric Down-welling short wave and long wave radiation radiation (W/m2).
- sw.albedo
numeric Albedo as a fraction of one (/1).
- lw.emissivity
numeric Emissivity of the surface (ground or vegetation) for long wave radiation.
- water.vp
numeric vector of water vapour pressure in air (Pa), ignored if
lw.down.irradiance
is available.- R_rel
numeric The ratio of actual and clear sky short wave irradiance (/1).
See also
Other Evapotranspiration and energy balance related functions.:
ET_ref()