photobiology (version 0.9.6)

day_night: Times for sun positions

Description

Functions for calculating the timing of solar positions by means of function sun_angles, given geographical coordinates and dates. They can be also used to find the time for an arbitrary solar elevation between 90 and -90 degrees by supplying "twilight" angle(s) as argument.

Usage

day_night(date = lubridate::today(), tz = "UTC", geocode = NULL,
  lon = 0, lat = 0, twilight = "none", unit.out = "date")

noon_time(date = lubridate::today(), tz = "UTC", geocode = NULL,
  lon = 0, lat = 0, twilight = NA, unit.out = "date")

sunrise_time(date = lubridate::today(), tz = "UTC", geocode = NULL,
  lon = 0, lat = 0, twilight = "none", unit.out = "date")

sunset_time(date = lubridate::today(), tz = "UTC", geocode = NULL,
  lon = 0, lat = 0, twilight = "none", unit.out = "date")

day_length(date = lubridate::today(), tz = "UTC", geocode = NULL,
  lon = 0, lat = 0, twilight = "none", unit.out = "hour")

night_length(date = lubridate::today(), tz = "UTC", geocode = NULL,
  lon = 0, lat = 0, twilight = "none", unit.out = "hour")

Arguments

date

array of POSIXct times or Date objects, any valid TZ is allowed, default is current date

tz

character string incading time zone to be used in output, default is system time zone

geocode

data frame with variables lon and lat as numeric values (degrees).

lon

numeric array of longitudes (degrees)

lat

numeric array of latitudes (degrees)

twilight

character string, one of "none", "civil", "nautical", "astronomical", or a numeric vector of length one, or two, giving solar elevation angle(s) in degrees (negative if below the horizon).

unit.out

charater string, One of "date", "hour", "minute", or "second".

Value

• day_night returns a list with fields sunrise time, sunset time, day length, night length. Each element of the list is a vector of the same length as the argument supplied for date. noon_time, sunrise_time and sunset_time return a vector of POSIXct times day_length and night_length return numeric a vector giving the length in hours

See Also

Other astronomy related functions: sun_angles

Examples

library(lubridate)
day_length()
day_length(ymd("2015-05-30"), lat = 60, lon = 25)
day_length(ymd("2014-12-30"), lat = 60, lon = 25)
day_length(ymd("2015-05-30"), lat = 60, lon = 25, twilight = "civil")
sunrise_time(ymd("2015-05-30"), lat = 60, lon = 25, tz = "EET")
day_night(ymd("2015-05-30"), lat = 60, lon = 25, twilight = "civil")