ClimMobTools (version 0.2-7)

GDD: Growing Degree Days

Description

Compute number of days required to reach growing degree days. GDD are calculated by taking the integral of warmth above a base temperature.

Usage

GDD(object, day.one = NULL, degree.days = NULL, base = NULL,
  span = NULL, ...)

Arguments

object

a numeric vector of geographic coordinates (lonlat) or an array with two dimensions containing the temperature data; 1st dimension contains the day temperature and 2nd dimension the night temperature. When lonlat is used, the function makes a call to nasapower::get_power to fetch and concatenate environmental data from NASA POWER (https://power.larc.nasa.gov/)

day.one

a vector of class 'Date' for the starting date to capture the environmental data

degree.days

an integer for the degree days required by the crop (look at the physiology of the focal crop)

base

an integer for the base temperature. Set 10 as default.

span

an integer or a vector with integers for the duration of the timespan to be captured

...

additional arguments passed to methods

Value

The number of days required to reach the growing degree days.

Examples

# NOT RUN {
library("ClimMobTools")
library("nasapower")

# random geographic locations around bbox(11, 12, 55, 58)
lonlat <- data.frame(lon = runif(10, 11, 12),
                     lat = runif(10, 55, 58))

# random planting dates around 2018-05-15 and 2018-05-20
pdates <- as.integer(runif(10, 17666, 17670))
pdates <- as.Date(pdates, origin = "1970-01-01")

# Calculate the days required for the plants in these plots to reach the
# maturity. The crop requires ~1800 degree days for it.

GDD(lonlat, 
    day.one = pdates,
    degree.days = 1800,
    base = 5)
# }
# NOT RUN {
    
# }