# Extremes: Sum of spell lengths exceeding daily threshold for... In ClimProjDiags: Set of Tools to Compute Various Climate Indices

 Extremes R Documentation

## Sum of spell lengths exceeding daily threshold for n-dimensional arrays

### Description

This function returns the number of spells of more than `min.length` days which exceed or are below the given `threshold` from daily data.

### Usage

``````Extremes(
data,
threshold,
op = ">",
min.length = 6,
spells.can.span.years = TRUE,
max.missing.days = 5,
dates = NULL,
timedim = NULL,
calendar = NULL,
ncores = NULL
)
``````

### Arguments

 `data` A n-dimensional array containing daily data. `threshold` A n-dimensional array with the threshold to be/not to be reach, usually given by the a percentile computed with the `Threshold` function. `op` The operator to use to compare data to threshold. `min.length` The minimum spell length to be considered. `spells.can.span.years` Whether spells can span years. `max.missing.days` Maximum number of NA values per time period. `dates` A vector of dates with a calendar attributes. If NULL (by default), the 'time' attributes of parameter 'data' are considered. `timedim` An integer number indicating the position of the time dimension in the parameter `data`. If NULL (by default), the dimension called 'time' in parameter `data`. `calendar` A character indicating the calendar type. `ncores` The number of cores to be used when computing the extreme.

### Details

This routine compares data to the thresholds using the given operator, generating a series of TRUE or FALSE values; these values are then filtered to remove any sequences of less than `min.length` days of TRUE values. It then computes the lengths of the remaining sequences of TRUE values (spells) and sums their lengths. The `spells.can.spa .years` option controls whether spells must always terminate at the end of a period, or whether they may continue until the criteria ceases to be met or the end of the data is reached. The default for fclimdex is FALSE.

### Value

A list of length 2:

• `\$output1`An array with the same dimensions as the original `data`, except the time dimension which is reduced to annual resolution given a timeseries of maximum spell lengths for each year.

• `\$year`A vector indicating the corresponding years.

### Examples

``````##Example synthetic data:
data <- 1:(2 * 3 * 310 * 1)
dim(data) <- c(time = 310, lon = 2, lat = 3, model = 1)
time <- as.POSIXct(paste(sort(rep(1902:1911, 31)), 1, 1:31, sep = "-"), tz = "CET")
metadata <- list(time = list(standard_name = 'time', long_name = 'time',
calendar = 'noleap',
units = 'days since 1970-01-01 00:00:00', prec = 'double',
dim = list(list(name = 'time', unlim = FALSE))))