This are defining a tropical year by the instant of the solstice in December 2010, and by the the length of the tropical year.

References:

tropical_year <- 
  list(
    time_ref = lubridate::ymd_hms("2010-12-21 23:38:00", tz="UTC"),
    dtime_ref = as.numeric(lubridate::ddays(365.242189)) 
   )
devtools::use_data(tropical_year, pkg = "..", overwrite = TRUE)


ijlyttle/groundTemp documentation built on May 18, 2019, 3:41 a.m.