R: Sum of spell lengths exceeding daily threshold

threshold.exceedance.duration.index {climdex.pcic} | R Documentation

## Sum of spell lengths exceeding daily threshold

### Description

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

### Usage

    threshold.exceedance.duration.index(daily.temp, date.factor, jdays, thresholds,
      op = ">", min.length = 6, spells.can.span.years = TRUE,
      max.missing.days)

### Arguments

`daily.temp` | Data to compute index on.
`date.factor` | Date factor to split by.
`jdays` | Timeseries of days of year.
`thresholds` | The thresholds to compare to.
`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.

### 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.span.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 timeseries of maximum spell lengths for each period.

### See Also

`climdex.wsdi`.

### Examples

    prec.dat <- c(0.1, 3.0, 4.3, 1.9, 1.3, 6.0, 0, 0, 4.0, 1)
    phony.date.factor <- factor(rep(1:2, each=5))

    ## With spells spanning years...
    alttedi <- threshold.exceedance.duration.index(prec.dat,
    phony.date.factor, rep(1:5, 2), rep(1, 5), ">=", 2, TRUE, 1)

    ## Without spells spanning years...
    tedi <- threshold.exceedance.duration.index(prec.dat, phony.date.factor,
    rep(1:5, 2), rep(1, 5), ">=", 2, FALSE, 1)

[Package climdex.pcic version 1.1-11 Index]