pollen (version 0.82.0)

gdd: Growing Degree Days Function

Description

This function calculates growing degree days (GDD) using the average of the daily maximum and minimum temperatures, a base temperature and a maximum base temperature

Usage

gdd(tmax, tmin, tbase, tbase_max, type = "C")

Arguments

tmax

daily maximum temperature

tmin

daily minimum temperature

tbase

base temperature

tbase_max

maximum base temperature

type

either "B", "C", or "D". The default is "C". Type "B" - The heat units are calculated based on the difference between the mean daily temperature and the threshold (`tbase`). In the case when the value of `tmin` is lower than `tbase`, then it is replaced by `tbase`. Type `"C"` - same as type `"B"` and when the value of `tmax` is larger than `tbase_max`, then it is replaced by `tbase_max`. Type `"D"`- same as type `"B"` and when the value of `tmax` is larger than `tbase_max`, then no heat units are added.

Value

a numeric vector with GDD values

References

Baskerville, G., & Emin, P. (1969). Rapid Estimation of Heat Accumulation from Maximum and Minimum Temperatures. Ecology, 50(3), 514-517. doi:10.2307/1933912

See Also

[base_temp()] for determining a base temperature

Examples

# NOT RUN {
set.seed(25)
df <- data.frame(tmax = runif(100, 6, 10), tmin = runif(100, 4, 6))

gdd(tmax = df$tmax, tmin = df$tmin, tbase = 5, tbase_max = 30)


# }