ETCCDI canonical index WSDI. Annual count of days in spans of at least six consecutive days where daily Tmax exceeds the 90th percentile of the calendar-day distribution from a reference period (default 1961 to 1990). The threshold is computed using a 5-day window centred on each calendar day, pooled across the reference period.
Arguments
- tmax
Numeric vector of daily maximum 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).
Details
Days inside qualifying spells are counted into the year they fall in; a spell that crosses a year boundary contributes to both years proportionally. Annual aggregation only.
Examples
set.seed(1)
dates <- seq(as.Date("1961-01-01"), as.Date("1991-12-31"), by = "day")
tmax <- 15 + 10 * sin(2 * pi * as.integer(format(dates, "%j")) / 365) +
rnorm(length(dates))
tail(ck_wsdi(tmax, dates))
#> period value index unit
#> 26 1986-01-01 0 wsdi days
#> 27 1987-01-01 0 wsdi days
#> 28 1988-01-01 0 wsdi days
#> 29 1989-01-01 0 wsdi days
#> 30 1990-01-01 0 wsdi days
#> 31 1991-01-01 0 wsdi days