photobiology: irrad_extraterrestrial – R documentation

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irrad_extraterrestrial

Extraterrestrial irradiance

Description

Estimate of down-welling solar (short wave) irradiance at the top of the atmosphere above a location on Earth, computed based on angles, Sun-Earth distance and the solar constant. Astronomical computations are done with function sun_angles().

Usage

irrad_extraterrestrial(
  time = lubridate::now(tzone = "UTC"),
  tz = lubridate::tz(time),
  geocode = tibble::tibble(lon = 0, lat = 51.5, address = "Greenwich"),
  solar.constant = "NASA"
)

Arguments

`time`	A "vector" of POSIXct Time, with any valid time zone (TZ) is allowed, default is current time.
`tz`	character string indicating time zone to be used in output.
`geocode`	data frame with variables lon and lat as numeric values (degrees), nrow > 1, allowed.
`solar.constant`	numeric or character If character, "WMO" or "NASA", if numeric, an irradiance value in the same units as the value to be returned.

Value

Numeric vector of extraterrestrial irradiance (in W / m2 if solar constant is a character value).

Examples

library(lubridate)

irrad_extraterrestrial(ymd_hm("2021-06-21 12:00", tz = "UTC"))

irrad_extraterrestrial(ymd_hm("2021-12-21 20:00", tz = "UTC"))

irrad_extraterrestrial(ymd_hm("2021-06-21 00:00", tz = "UTC") + hours(1:23))

photobiology

Photobiological Calculations

v0.10.10

GPL (>= 2)

Authors

Pedro J. Aphalo [aut, cre] (<https://orcid.org/0000-0003-3385-972X>), Titta K. Kotilainen [ctb] (<https://orcid.org/0000-0002-2822-9734>), Glenn Davis [ctb], Agnese Fazio [ctb]

Initial release

2022-03-24