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Calculate Growing Degree Days (GDD)

Source: R/gdd.R
gdd.Rd

Calculate the number of growing degree days to the specified end date.

Usage

gdd(
  x,
  start_date = as.Date("1972-03-01"),
  end_date = as.Date("1972-09-30"),
  min_length = NULL,
  ignore_truncation = FALSE,
  start_temp = 5,
  end_temp = 4,
  window_width = 7,
  pick = "all",
  msgs = TRUE
)

Arguments

x

A data frame with two columns date and temperature. date, which must be of class Date provides the dates and temperature which must be a numeric vector provides the mean daily water temperature in degrees centigrade.

start_date

A Date scalar of the first date within each year to consider (the year is ignored). #' If start_date occurs before the end_date (when ignoring the year) then the window is considered to span two calendar years.

end_date

A Date scalar of the last date within each year to consider (the year is ignored).

min_length

A whole number of the minimum length to consider. Must be at least twice the window width but no more than 365. If NULL then set to be the difference between start_date and end_date (ignoring the year).

ignore_truncation

A flag specifying whether to ignore start truncation (end truncation is always ignored).

start_temp

A positive real number of the average water temperature at the start of the growing season(s) in C.

end_temp

A positive real number of the average water temperature at the end of the growing season(s) in C. It must be greater than or equal to the start temperature.

window_width

A positive whole number of the width of the rolling mean window in days. By default 7.

pick

A string specifying whether to pick the "longest", "shortest", "first" or "last" 'season' or the season with the "biggest" or "smallest" GSDD. By default the returned value is the the GSDD value for the "longest" 'season'.

msgs

A flag specifying whether to provide messages.

Value

A tibble with two columns year and gdd.

See also

gsdd()

Examples

gdd(gsdd::temperature_data)
#> # A tibble: 1 × 2
#>    year   gdd
#>   <int> <dbl>
#> 1  2019 3605.