Computes growing degree days, the temperature-limited radiation use efficiency factor, and daily temperature range.
Usage
param_temperature(
env.data,
Tmax = NULL,
Tmin = NULL,
Tbase1 = 9,
Tbase2 = 45,
Topt1 = 26,
Topt2 = 32,
method = c("standard", "legacy"),
merge = FALSE,
verbose = TRUE
)Arguments
- env.data
data.frame. A
get_weatheroutput or equivalent.- Tmax, Tmin
character. Column names for maximum and minimum air temperature (Celsius).
- Tbase1
numeric. Base temperature below which development stops.
- Tbase2
numeric. Upper temperature at which development stops.
- Topt1, Topt2
numeric. Lower and upper bounds of the optimal range.
- method
character. GDD formulation:
"standard"(default) or"legacy". See Details.- merge
boolean. Bind results onto
env.data.- verbose
boolean. Print a summary of what was computed.
Details
GDD methods.
"standard"\(GDD = \max(\frac{\min(T_{max}, T_{base2}) + T_{min}}{2} - T_{base1},\ 0)\). Tmax is capped at the upper threshold; the result is floored at zero. This is the conventional agronomic definition.
"legacy"Clamps both Tmax and Tmin into \([T_{base1}, T_{base2}]\) before averaging. This is the behaviour of earlier EnvRtype versions and corresponds to the "Method 2" variant. It credits heat units on days colder than \(T_{base1}\) – e.g. with Tmax 12, Tmin 5, Tbase1 9 it returns 1.5 where the standard method returns 0.
The default changed from legacy to standard; results will differ on cold days.
Pass method = "legacy" to reproduce earlier output.
FRUE rises linearly from 0 at Tbase1 to 1 at Topt1, holds at
1 across the optimum, and falls to 0 at Tbase2.
Examples
# \donttest{
env.data <- get_weather(lat = -13.05, lon = -56.05)
#> ---------------------------------------------------------------
#> get_weather -- downloads daily weather from NASA POWER
#> Last updated at 09/27/2026
#> ---------------------------------------------------------------
#> start.day is NULL; matched as 2024-01-26
#> end.day is NULL; matched as 2024-02-25
#> ---------------------------------------------------------------
#> get_weather() - daily weather from NASA POWER
#> https://docs.ropensci.org/nasapower
#> ---------------------------------------------------------------
#> Start .............................. Thu Oct 22 18:34:53 2026
#> Environmental units ................ 1
#> Parallel ........................... [ ]
#> [1/1] env1 downloaded
#> Computing VPD ...................... [ x ]
#> Computing N, RTA ................... [ x ]
#> Computing n ........................ [ x ]
#> Computing TH1 ...................... [ x ]
#> Computing TH2 ...................... [ x ]
#> Computing PAR_TEMP ................. [ x ]
#> Environmental units downloaded ..... 1/1
#> Daily weather features ............. 25
#> Done ............................... Thu Oct 22 18:34:53 2026
#> Total time ......................... 0.93s
param_temperature(env.data)
#> ---------------------------------------------------------------
#> param_temperature -- derives temperature-response parameters
#> Last updated at 09/27/2026
#> ---------------------------------------------------------------
#> ----------------------------------------------------------------------
#> Growing Degree Day (GDD, C/day) - method: standard
#> Effect of temperature on radiation use efficiency (FRUE, 0-1)
#> Daily temperature range (T2M_RANGE, C)
#> ----------------------------------------------------------------------
#> GDD FRUE T2M_RANGE
#> 1 18.335 1.0000000 10.03
#> 2 18.225 1.0000000 11.21
#> 3 18.430 1.0000000 11.12
#> 4 17.790 1.0000000 9.00
#> 5 18.670 1.0000000 10.94
#> 6 18.455 1.0000000 9.05
#> 7 19.595 1.0000000 12.83
#> 8 17.355 1.0000000 6.11
#> 9 16.715 0.9832353 6.73
#> 10 15.595 0.9173529 5.21
#> 11 14.975 0.8808824 5.41
#> 12 16.105 0.9473529 8.17
#> 13 17.415 1.0000000 9.45
#> 14 17.370 1.0000000 9.38
#> 15 17.635 1.0000000 8.49
#> 16 17.805 1.0000000 8.05
#> 17 16.505 0.9708824 4.45
#> 18 16.505 0.9708824 6.23
#> 19 16.880 0.9929412 9.44
#> 20 17.705 1.0000000 9.69
#> 21 18.060 1.0000000 9.92
#> 22 18.095 1.0000000 10.17
#> 23 18.510 1.0000000 9.88
#> 24 16.155 0.9502941 9.05
#> 25 16.640 0.9788235 5.80
#> 26 16.520 0.9717647 7.60
#> 27 17.060 1.0000000 7.24
#> 28 17.535 1.0000000 6.63
#> 29 17.085 1.0000000 6.55
#> 30 16.705 0.9826471 6.25
#> 31 17.335 1.0000000 9.21
param_temperature(env.data, method = "legacy") # pre-refactor behaviour
#> ---------------------------------------------------------------
#> param_temperature -- derives temperature-response parameters
#> Last updated at 09/27/2026
#> ---------------------------------------------------------------
#> ----------------------------------------------------------------------
#> Growing Degree Day (GDD, C/day) - method: legacy
#> Effect of temperature on radiation use efficiency (FRUE, 0-1)
#> Daily temperature range (T2M_RANGE, C)
#> ----------------------------------------------------------------------
#> GDD FRUE T2M_RANGE
#> 1 18.335 1.0000000 10.03
#> 2 18.225 1.0000000 11.21
#> 3 18.430 1.0000000 11.12
#> 4 17.790 1.0000000 9.00
#> 5 18.670 1.0000000 10.94
#> 6 18.455 1.0000000 9.05
#> 7 19.595 1.0000000 12.83
#> 8 17.355 1.0000000 6.11
#> 9 16.715 0.9832353 6.73
#> 10 15.595 0.9173529 5.21
#> 11 14.975 0.8808824 5.41
#> 12 16.105 0.9473529 8.17
#> 13 17.415 1.0000000 9.45
#> 14 17.370 1.0000000 9.38
#> 15 17.635 1.0000000 8.49
#> 16 17.805 1.0000000 8.05
#> 17 16.505 0.9708824 4.45
#> 18 16.505 0.9708824 6.23
#> 19 16.880 0.9929412 9.44
#> 20 17.705 1.0000000 9.69
#> 21 18.060 1.0000000 9.92
#> 22 18.095 1.0000000 10.17
#> 23 18.510 1.0000000 9.88
#> 24 16.155 0.9502941 9.05
#> 25 16.640 0.9788235 5.80
#> 26 16.520 0.9717647 7.60
#> 27 17.060 1.0000000 7.24
#> 28 17.535 1.0000000 6.63
#> 29 17.085 1.0000000 6.55
#> 30 16.705 0.9826471 6.25
#> 31 17.335 1.0000000 9.21
# }