tt_apsim_met {apsimx} | R Documentation |
Calculates Thermal Time taking a ‘met’ object
Description
Calculates Thermal Time using the ‘Classic’ formula, Heat Stress, Crop Heat Unit and other methods
Usage
tt_apsim_met(
met,
dates,
method = c("Classic_TT", "HeatStress_TT", "CropHeatUnit_TT", "APSIM_TT", "CERES_TT",
"all"),
x_temp = c(0, 26, 34),
y_tt = c(0, 26, 0),
base_temp = 0,
max_temp = 30,
dates.format = c("%d-%m")
)
Arguments
met |
object of class ‘met’ |
dates |
when the calculation starts and when it ends. At the moment it needs to be a character vector (e.g. c(‘01-05’, ‘10-10’)). It will use the same dates every year for multiple years. |
method |
one of ‘Classic_TT’, ‘HeatStress_TT’, ‘ASPIM_TT’, ‘CERES_TT’ and ‘all’ |
x_temp |
cardinal temperatures (base, optimal and maximum) |
y_tt |
thermal time accumulation for cardinal temperatures |
base_temp |
base temperature for Classic TT calculation |
max_temp |
maximum temperature for Classic TT calculation |
dates.format |
default is ‘%d-%m’ which means day and month |
Details
Calculating Thermal Time using a variety of methods. The function will fail if the method is not selected. Also, it does not work if each year does not have at least 365 days.
Value
it returns an object of class ‘met’ with additional columns ‘Date’ and the corresponding TT calculation
References
Abendroth, L.J., Miguez, F.E., Castellano, M.J. and Hatfield, J.L. (2019), Climate Warming Trends in the U.S. Midwest Using Four Thermal Models. Agron. J., 111: 3230-3243. (doi:10.2134/agronj2019.02.0118)
Examples
## Not run:
require(nasapower)
require(ggplot2)
pwr <- get_power_apsim_met(lonlat = c(-93,42), dates = c("2012-01-01","2015-12-31"))
check_apsim_met(pwr)
pwr <- impute_apsim_met(pwr)
pwr2 <- tt_apsim_met(pwr, dates = c("01-05", "30-10"), method = c("Classic", "Heat"))
ggplot(data = pwr2, aes(x = Date, y = Classic_TT)) + geom_point()
ggplot(data = pwr2, aes(x = Date, y = HeatStress_TT)) + geom_point()
## End(Not run)