climdex.csdi: Cold Spell Duration Index

In climdex.pcic: PCIC Implementation of Climdex Routines

Description

This function computes the climdex index CSDI.

Usage

climdex.csdi(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 CSDI (Cold Spell Duration Index).

The cold spell duration index is defined as the number of days each year which are part of a "cold spell". A "cold spell" is defined as a sequence of 6 or more days in which the daily minimum temperature is below the 10th percentile of daily minimum 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 cold spell duration index.
csdi <- climdex.csdi(ci)

Example output

Loading required package: PCICt

climdex.pcic documentation built on March 26, 2020, 7:17 p.m.