Rg.to.PPFD: Conversions between Global Radiation and Photosynthetic...

In bigleaf: Physical and Physiological Ecosystem Properties from Eddy Covariance Data

Conversions between Global Radiation and Photosynthetic Photon Flux Density

Description

Converts radiation from W m-2 to umol m-2 s-1 and vice versa.

Usage

Rg.to.PPFD(Rg, J_to_mol = 4.6, frac_PAR = 0.5)

PPFD.to.Rg(PPFD, J_to_mol = 4.6, frac_PAR = 0.5)

Arguments

Rg	Global radiation = incoming short-wave radiation at the surface (W m-2)
J_to_mol	Conversion factor from J m-2 s-1 (= W m-2) to umol (quanta) m-2 s-1
frac_PAR	Fraction of incoming solar irradiance that is photosynthetically active radiation (PAR); defaults to 0.5
PPFD	Photosynthetic photon flux density (umol m-2 s-1)

Details

The conversion is given by:

PPFD = Rg * frac_PAR * J_to_mol

by default, the combined conversion factor (frac_PAR * J_to_mol) is 2.3

Examples

# convert a measured incoming short-wave radiation of 500 Wm-2 to
# PPFD in umol m-2 s-1 and backwards
Rg.to.PPFD(500)
PPFD.to.Rg(1150)

bigleaf documentation built on Aug. 22, 2022, 9:09 a.m.