Fluence

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Description

This function returns the energy or photon fluence for a given waveband of a light source spectrum and the duration of the exposure.

Usage

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fluence(spct, w.band, unit.out, exposure.time, wb.trim, use.cached.mult,
  use.hinges, allow.scaled, ...)

## Default S3 method:
fluence(spct, w.band, unit.out, exposure.time, wb.trim,
  use.cached.mult, use.hinges, allow.scaled, ...)

## S3 method for class 'source_spct'
fluence(spct, w.band = NULL,
  unit.out = getOption("photobiology.radiation.unit", default = "energy"),
  exposure.time, wb.trim = getOption("photobiology.waveband.trim", default =
  TRUE), use.cached.mult = getOption("photobiology.use.cached.mult", default =
  FALSE), use.hinges = NULL, allow.scaled = FALSE, ...)

## S3 method for class 'source_mspct'
fluence(spct, w.band = NULL,
  unit.out = getOption("photobiology.radiation.unit", default = "energy"),
  exposure.time, wb.trim = getOption("photobiology.waveband.trim", default =
  TRUE), use.cached.mult = getOption("photobiology.use.cached.mult", default =
  FALSE), use.hinges = NULL, allow.scaled = FALSE, ...,
  idx = !is.null(names(spct)))

Arguments

spct

an R object

w.band

a list of waveband objects or a waveband object

unit.out

character string with allowed values "energy", and "photon", or its alias "quantum"

exposure.time

lubridate::duration

wb.trim

logical if TRUE wavebands crossing spectral data boundaries are trimmed, if FALSE, they are discarded

use.cached.mult

logical indicating whether multiplier values should be cached between calls

use.hinges

logical indicating whether to use hinges to reduce interpolation errors

allow.scaled

logical indicating whether scaled or normalized spectra as argument to spct are flagged as an error

...

other arguments (possibly ignored)

idx

logical whether to add a column with the names of the elements of spct

Value

One numeric value for each waveband with no change in scale factor, with name attribute set to the name of each waveband unless a named list is supplied in which case the names of the list elements are used. The time.unit attribute is copied from the spectrum object to the output. Units are as follows: If time.unit is second, [W m-2 nm-1] -> [mol s-1 m-2] If time.unit is day, [J d-1 m-2 nm-1] -> [mol d-1 m-2]

Methods (by class)

  • default: Default for generic function

  • source_spct: Calculate photon fluence from a source_spct object and the duration of the exposure

  • source_mspct: Calculates fluence from a source_mspct object.

Note

The last two parameters control speed optimizations. The defaults should be suitable in mosts cases. 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 irradiance functions: e_fluence, e_irrad, energy_irradiance, irradiance, irrad, photon_irradiance, q_fluence, q_irrad

Examples

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library(lubridate)
fluence(sun.spct,
        w.band = waveband(c(400,700)),
        exposure.time = lubridate::duration(3, "minutes") )

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