R: Warm Spell Duration Index

climdex.wsdi {climdex.pcic} | R Documentation

## Warm Spell Duration Index

### Description

This function computes the climdex index WSDI.

### Usage

    climdex.wsdi(ci, spells.can.span.years = FALSE)

### Arguments

`ci` | Object of type climdexInput.
`spells.can.span.years` | Whether to allow spells of dry/wet days to span years.

### Details

This function takes a climdexInput object as input and computes the climdex index WSDI (Warm Spell Duration Index).

The warm spell duration index is defined as the number of days each year which are part of a "warm spell". A "warm spell" is defined as a sequence of 6 or more days in which the daily maximum temperature exceeds the 90th percentile of daily maximum temperature for a 5-day running window surrounding this day during the baseline period.

The `spells.can.span.years` option specifies whether spells can cross year boundaries – i.e., span years. The default for this is the same as fclimdex.

### Value

A vector containing the value of the index for each year.

### Note

These functions may calculate slightly different results than fclimdex.

Behaviour of climdex.wsdi and climdex.csdi differ somewhat from fclimdex. fclimdex considers all days in a warm or cold spell to be part of the year in which the spell ended. climdex.wsdi and climdex.csdi split the spell such that days in each spell are allocated to the separate years in the days occurred.

### References

http://etccdi.pacificclimate.org/list_27_indices.shtml

### See Also

`climdexInput.raw`, `climdexInput.csv`, `threshold.exceedance.duration.index`.

### Examples

    library(PCICt)

    ## Create a climdexInput object from some data already loaded in and
    ## ready to go.

    ## Parse the dates into PCICt.
    tmax.dates <- as.PCICt(do.call(paste, ec.1018935.tmax[,c("year",
    "jday")]), format="%Y %j", cal="gregorian")
    tmin.dates <- as.PCICt(do.call(paste, ec.1018935.tmin[,c("year",
    "jday")]), format="%Y %j", cal="gregorian")
    prec.dates <- as.PCICt(do.call(paste, ec.1018935.prec[,c("year",
    "jday")]), format="%Y %j", cal="gregorian")

    ## Load the data in.
    ci <- climdexInput.raw(ec.1018935.tmax$MAX_TEMP,
    ec.1018935.tmin$MIN_TEMP, ec.1018935.prec$ONE_DAY_PRECIPITATION,
    tmax.dates, tmin.dates, prec.dates, base.range=c(1971, 2000))

    ## Create an annual timeseries of the warm spell duration index.
    wsdi <- climdex.wsdi(ci)

[Package climdex.pcic version 1.1-11 Index]