tt_apsim_met: Calculates Thermal Time taking a 'met' object

In apsimx: Inspect, Read, Edit and Run 'APSIM' "Next Generation" and 'APSIM' Classic

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)

apsimx documentation built on Sept. 11, 2024, 5:42 p.m.