waveband_ratio: Photon or energy ratio

In photobiology: Photobiological Calculations

Photon or energy ratio

Description

This function gives the (energy or photon) irradiance ratio between two given wavebands of a radiation spectrum.

Usage

waveband_ratio(
  w.length,
  s.irrad,
  w.band.num = NULL,
  w.band.denom = NULL,
  unit.out.num = NULL,
  unit.out.denom = unit.out.num,
  unit.in = "energy",
  check.spectrum = TRUE,
  use.cached.mult = FALSE,
  use.hinges = getOption("photobiology.use.hinges", default = NULL)
)

Arguments

w.length	numeric Vector of wavelengths [nm].
s.irrad	numeric vector of spectral irradiances in [W\,m^{-2}\,nm^{-1}] or [mol\,s^{-1}\,sm^{-2}\,nm^{-1}] as indicated by the argument pased to unit.in.
w.band.num, w.band.denom	waveband objects used to compute the numerator and denominator of the ratio.
unit.out.num, unit.out.denom	character Base of expression used to compute the numerator and denominator of the ratio. Allowed values "energy", and "photon", or its alias "quantum".
unit.in	character Allowed values "energy", and "photon", or its alias "quantum".
check.spectrum	logical Flag indicating whether to sanity check input data, default is TRUE.
use.cached.mult	logical Flag indicating whether multiplier values should be cached between calls.
use.hinges	logical Flag indicating whether to insert "hinges" into the spectral data before integration so as to reduce interpolation errors at the boundaries of the wavebands.

Value

a single numeric value giving the ratio

Note

The default for both w.band parameters is a waveband covering the whole range of w.length. From version 0.9.19 onwards use of this default does not trigger a warning, but instead is used silently.

Examples

# photon:photon ratio
with(sun.data,
     waveband_ratio(w.length, s.e.irrad,
                    new_waveband(400,500),
                    new_waveband(400,700), "photon"))
# energy:energy ratio
with(sun.data,
     waveband_ratio(w.length, s.e.irrad,
                    new_waveband(400,500),
                    new_waveband(400,700), "energy"))
# energy:photon ratio
with(sun.data,
     waveband_ratio(w.length, s.e.irrad,
                    new_waveband(400,700),
                    new_waveband(400,700),
                    "energy", "photon"))
# photon:photon ratio waveband : whole spectrum
with(sun.data,
     waveband_ratio(w.length, s.e.irrad,
                    new_waveband(400,500),
                    unit.out.num="photon"))
# photon:photon ratio of whole spectrum should be equal to 1.0
with(sun.data,
     waveband_ratio(w.length, s.e.irrad,
     unit.out.num="photon"))

photobiology documentation built on June 8, 2025, 10:14 a.m.