Convert DateTime from local solar time to UTC — convert_solartime_to

Convert DateTime to UTC from local solar time, which may be either apparent solar (perfect match between noon and solar zenith) or mean solar (exactly 24 hours between solar noons).

Usage

convert_solartime_to_UTC(
  any.solar.time,
  longitude,
  time.type = c("apparent solar", "mean solar")
)

Arguments

any.solar.time: either apparent or mean solar time (specified by time.type); date-time values in POSIXct format. Timezone must be UTC.
longitude: numeric, in degrees, either positive and unitted ("degE" or "degW") or with sign indicating direction (positive = East), describing location of the site
time.type: character indicating whether any.solar.time values are in apparent or mean solar time. "apparent solar", i.e. true solar time, is noon when the sun is at its zenith. "mean solar" approximates apparent solar time but with noons exactly 24 hours apart.

Value

a POSIXct object in UTC

References

Yard, Bennett, Mietz, Coggins, Stevens, Hueftle, and Blinn. 2005. Influence of topographic complexity on solar insolation estimates for the Colorado River, Grand Canyon, AZ. Ecological Modelling.