net_irradiance: Net radiation flux

In photobiology: Photobiological Calculations

Net radiation flux

Description

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).

Value

A numeric vector of evapotranspiration estimates expressed as W / m-2.

See Also

Other Evapotranspiration and energy balance related functions.: ET_ref()

photobiology documentation built on Oct. 21, 2023, 1:06 a.m.