ck_tn90p: Percentage of Warm Nights (TN90p)

In climatekit: Unified Climate Indices for Temperature, Precipitation, and Drought

Percentage of Warm Nights (TN90p)

Description

ETCCDI canonical index TN90p. Percentage of days where daily Tmin exceeds the 90th percentile of the calendar-day distribution from a reference period (default 1961 to 1990). Computation follows the same convention as ck_tx10p() and supports the same bootstrap argument.

Usage

ck_tn90p(
  tmin,
  dates,
  ref_start = 1961L,
  ref_end = 1990L,
  period = "annual",
  bootstrap = FALSE
)

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.
period	Character. Aggregation period: "annual" (default) or "monthly".
bootstrap	Logical. If TRUE, apply the Zhang (2005) in-base bootstrap correction. Default FALSE for backward compatibility and speed.

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_tn90p(tmin, dates))

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