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()
.
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).
See also
Function sun_angles
.
Examples
library(lubridate)
irrad_extraterrestrial(ymd_hm("2021-06-21 12:00", tz = "UTC"))
#> [1] 1161.983
irrad_extraterrestrial(ymd_hm("2021-12-21 20:00", tz = "UTC"))
#> [1] 0
irrad_extraterrestrial(ymd_hm("2021-06-21 00:00", tz = "UTC") + hours(1:23))
#> [1] 0.00000 0.00000 0.00000 28.78267 209.56415 403.99302
#> [7] 598.82306 780.78084 937.47001 1058.21579 1134.79222 1161.98253
#> [13] 1137.93449 1064.28664 946.05654 791.29897 610.55716 416.14444
#> [19] 221.30541 39.31359 0.00000 0.00000 0.00000