ck_csdi: Cold Spell Duration Index (CSDI)
In climatekit: Unified Climate Indices for Temperature, Precipitation, and Drought

ck_csdi

R Documentation

Cold Spell Duration Index (CSDI)

Description

ETCCDI canonical index CSDI. Annual count of days in spans of at least six consecutive days where daily Tmin falls below the 10th percentile of the calendar-day distribution from a reference period (default 1961 to 1990). Cold-side counterpart to ck_wsdi().

Usage

ck_csdi(tmin, dates, ref_start = 1961L, ref_end = 1990L, min_spell = 6L)

Arguments

`tmin`	Numeric vector of daily minimum temperatures (degrees C).
`dates`	Date vector of the same length as `tmax`. Must contain data covering the reference period.
`ref_start`, `ref_end`	Integer. Reference period boundary years (inclusive). Defaults to 1961 and 1990.
`min_spell`	Integer. Minimum spell length in days (default 6, the ETCCDI standard).

Value

A data frame with columns period, value, index, and unit.

Examples

set.seed(1)
dates <- seq(as.Date("1961-01-01"), as.Date("1991-12-31"), by = "day")
tmin <- 5 + 8 * sin(2 * pi * as.integer(format(dates, "%j")) / 365) +
        rnorm(length(dates))
tail(ck_csdi(tmin, dates))

climatekit documentation built on May 9, 2026, 5:08 p.m.