tidyextreme (version 1.0.0)

calculate_CSDI: Calculate Cold Spell Duration Index (CSDI)

Description

Calculates the number of days with at least 6 consecutive days where temperature is below the 10th percentile, following ETCCDI definition CSDI.

Usage

calculate_CSDI(
  df,
  frequency = "daily",
  time_col = NULL,
  tmin_col = NULL,
  temp_col = NULL,
  window_days = 30,
  min_consecutive = 6
)

Value

A tibble with columns: year, CSDI, n_spells, mean_spell_length

Arguments

df

Data frame with climate data

frequency

Temporal frequency: "daily" or "hourly" (string)

time_col

Name of the time column (string). For daily frequency, the column should be of class Date or a string in the format YYYY-MM-DD. For hourly frequency, the column should be of class POSIXct or a string in the format YYYY-MM-DD HH:MM:SS.

tmin_col

Name of minimum temperature column (daily data) (string)

temp_col

Name of temperature column (for single temp or hourly) (string)

window_days

Window size for percentile calculation (default: 30)

min_consecutive

Minimum consecutive days for cold spell (default: 6)

Examples

# Daily data with minimum temperature
set.seed(123)
daily_data <- data.frame(
  date = seq(as.Date("2000-01-01"), as.Date("2002-12-31"), by = "day"),
  tmin = 15 + 8 * sin(seq(0, 4*pi, length.out = 1096)) + rnorm(1096, 0, 3)
)

calculate_CSDI(
  df = daily_data,
  frequency = "daily",
  time_col = "date",
  tmin_col = "tmin"
)

# With custom window and consecutive days
calculate_CSDI(
  df = daily_data,
  frequency = "daily",
  time_col = "date",
  tmin_col = "tmin",
  window_days = 15,
  min_consecutive = 5
)