| CST_TotalTimeExceedingThreshold {CSIndicators} | R Documentation |
Total Time of a variable Exceeding (not exceeding) a Threshold
Description
The Total Time of a variable exceeding (or not) a Threshold. It returns the
total number of days (if the data provided is daily, or the corresponding
units of the data frequency) that a variable is exceeding a threshold
during a period. The threshold provided must be in the same units as the
variable units, i.e. to use a percentile as a scalar, the function
AbsToProbs or QThreshold may be needed (see examples).
Providing maximum temperature daily data, the following agriculture
indices for heat stress can be obtained by using this function:
'SU35', Total count of days when daily maximum temperatures exceed 35°C in the seven months from the start month given (e.g. from April to October for start month of April).
'SU36', Total count of days when daily maximum temperatures exceed 36 between June 21st and September 21st.
'SU40', Total count of days when daily maximum temperatures exceed 40 between June 21st and September 21st.
'Spr32', Total count of days when daily maximum temperatures exceed 32 between April 21st and June 21st.
Usage
CST_TotalTimeExceedingThreshold(
data,
threshold,
op = ">",
start = NULL,
end = NULL,
time_dim = "time",
na.rm = FALSE,
ncores = NULL
)
Arguments
data |
An 's2dv_cube' object as provided function |
threshold |
If only one threshold is used, it can be an 's2dv_cube' object or a multidimensional array with named dimensions. It must be in the same units and with the common dimensions of the same length as parameter 'data'. It can also be a vector with the same length of 'time_dim' from 'data' or a scalar. If we want to use two thresholds: it can be a vector of two scalars, a list of two vectors with the same length of 'time_dim' from 'data' or a list of two multidimensional arrays with the common dimensions of the same length as parameter 'data'. If two thresholds are used, parameter 'op' must be also a vector of two elements. |
op |
An operator '>' (by default), '<', '>=' or '<='. If two thresholds are used it has to be a vector of a pair of two logical operators: c('<', '>'), c('<', '>='), c('<=', '>'), c('<=', '>='), c('>', '<'), c('>', '<='), c('>=', '<'),c('>=', '<=')). |
start |
An optional parameter to define the initial date of the period
to select from the data by providing a list of two elements: the initial
date of the period and the initial month of the period. By default it is set
to NULL and the indicator is computed using all the data provided in
|
end |
An optional parameter to define the final date of the period to
select from the data by providing a list of two elements: the final day of
the period and the final month of the period. By default it is set to NULL
and the indicator is computed using all the data provided in |
time_dim |
A character string indicating the name of the dimension to compute the indicator. By default, it is set to 'time'. It can only indicate one time dimension. |
na.rm |
A logical value indicating whether to ignore NA values (TRUE) or not (FALSE). |
ncores |
An integer indicating the number of cores to use in parallel computation. |
Value
An 's2dv_cube' object containing in element data the total
number of the corresponding units of the data frequency that a variable is
exceeding a threshold during a period with dimensions of the input parameter
'data' except the dimension where the indicator has been computed. The
'Dates' array is updated to the dates corresponding to the beginning of the
aggregated time period. A new element called 'time_bounds' will be added into
the 'attrs' element in the 's2dv_cube' object. It consists of a list
containing two elements, the start and end dates of the aggregated period with
the same dimensions of 'Dates' element.
Examples
exp <- NULL
exp$data <- array(rnorm(5 * 3 * 214 * 2)*23,
c(member = 5, sdate = 3, time = 214, lon = 2))
exp$attrs$Dates <- c(seq(as.Date("01-05-2000", format = "%d-%m-%Y"),
as.Date("30-11-2000", format = "%d-%m-%Y"), by = 'day'),
seq(as.Date("01-05-2001", format = "%d-%m-%Y"),
as.Date("30-11-2001", format = "%d-%m-%Y"), by = 'day'),
seq(as.Date("01-05-2002", format = "%d-%m-%Y"),
as.Date("30-11-2002", format = "%d-%m-%Y"), by = 'day'))
dim(exp$attrs$Dates) <- c(sdate = 3, time = 214)
class(exp) <- 's2dv_cube'
DOT <- CST_TotalTimeExceedingThreshold(exp, threshold = 23, start = list(21, 4),
end = list(21, 6))