Calculate modeled light from solar.time — calc

Calculate photosynthetically active radiation (PAR) for a series of date-times and site coordinates.

Usage

calc_light(
  solar.time,
  latitude,
  longitude,
  max.PAR = 2326,
  attach.units = deprecated()
)

solar.time: Mean solar time, as required for input to metabolism models. See mm_data() and calc_solar_time().
latitude: Numeric value or vector indicating the site latitude in decimal degrees (never radians or deg-min-sec, no matter what format is) between -90 (South Pole) and 90 (North Pole).
longitude: Numeric, in degrees, either positive and unitted ("degE" or "degW") or with sign indicating direction (positive = East), describing location of the site.
max.PAR: Numeric or unitted_numeric: the PAR (umol m^-2 s^-1) that each day should reach at peak light.
attach.units: Deprecated. A logical. Should the returned vector be a unitted object?

A numeric vector of modeled PAR values in µmol m⁻² s⁻¹.

solar.time <- lubridate::force_tz(as.POSIXct('2016-09-27 12:00'), 'UTC')
calc_light(solar.time, 40, -120)
#> [1] 1720.981