Wavelength-range definition for purple radiation according to ISO or imagers in the Landsat satellites.
Details
Purple (or violet) wavelengths as defined by ISO standards based on human vision overlap the UVA band as defined by a separate ISO standard. In other contexts like plant photobiology purple is included under blue, while some overoptimistic LED sellers call LEDs emitting in the violet region ultraviolet LEDs. In addition to the ISO definition of purple, a purple channel from Landsat imagers is implemented.
Examples
Purple()
#> Purple.ISO
#> low (nm) 360
#> high (nm) 450
#> weighted none
Purple("ISO")
#> Purple.ISO
#> low (nm) 360
#> high (nm) 450
#> weighted none
e_irrad(sun.spct, Purple()) # W m-2
#> E_Purple.ISO
#> 47.75529
#> attr(,"time.unit")
#> [1] "second"
#> attr(,"radiation.unit")
#> [1] "total energy irradiance"
q_irrad(sun.spct, Purple()) # mol m-2
#> Q_Purple.ISO
#> 0.0001639893
#> attr(,"time.unit")
#> [1] "second"
#> attr(,"radiation.unit")
#> [1] "total photon irradiance"
q_irrad(sun.spct, Purple(), scale.factor = 1e6) # umol m-2
#> Q_Purple.ISO
#> 163.9893
#> attr(,"time.unit")
#> [1] "second"
#> attr(,"radiation.unit")
#> [1] "total photon irradiance"