R: Photon irradiance for split spectrum regions

split_photon_irradiance {photobiology} | R Documentation

## Photon irradiance for split spectrum regions

### Description

This function returns the photon irradiance for a series of contiguous wavebands from a radiation spectrum. The returned values can be either absolute or relative to their sum.

### Usage

    split_photon_irradiance(w.length, s.irrad, cut.w.length = range(w.length),
      unit.in = "energy", scale = "absolute", 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 (energy or photon) irradiance values (W m-2 nm-1).
`cut.w.length` | numeric vector of wavelengths (nm).
`unit.in` | character Allowed values "energy", and "photon", or its alias "quantum".
`scale` | a character A string indicating the scale used for the returned values ("absolute", "relative", "percent").
`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 numeric vector of photon irradiances with no change in scale factor: [W m-2 nm-1] -> [mol s-1 m-2], [mol s-1 m-2 nm-1] -> [mol s-1 m-2] or relative values (fraction of one based on photon units) if scale = "relative" or scale = "percent".

### Note

The last three parameters control speed optimizations. The defaults should be suitable in most cases. If you set `check.spectrum=FALSE` then you should call `check_spectrum` at least once for your spectrum before using any of the other functions. If you will use repeatedly the same SWFs on many spectra measured at exactly the same wavelengths you may obtain some speed up by setting `use.cached.mult=TRUE`. However, be aware that you are responsible for ensuring that the wavelengths are the same in each call, as the only test done is for the length of the `w.length` vector.

### See Also

Other low-level functions operating on numeric vectors.: `as_energy`, `as_quantum_mol`, `calc_multipliers`, `div_spectra`, `energy_irradiance`, `energy_ratio`, `insert_hinges`, `integrate_xy`, `interpolate_spectrum`, `irradiance`, `l_insert_hinges`, `oper_spectra`, `photon_irradiance`, `photon_ratio`, `photons_energy_ratio`, `prod_spectra`, `s_e_irrad2rgb`, `split_energy_irradiance`, `subt_spectra`, `sum_spectra`, `trim_tails`, `v_insert_hinges`

### Examples

    with(sun.data,
         split_photon_irradiance(w.length, s.e.irrad,
                 cut.w.length = c(300, 400, 500, 600, 700)))
    with(sun.data,
         split_photon_irradiance(w.length, s.e.irrad))

[Package photobiology version 0.9.21 Index]