Mean diurnal cycle of an hourly meteorological record — build_diurnal

Summarises an hourly record into, for each variable and calendar month, the average shape of the day: an anomaly about the daily mean for additive variables (temperature, humidity, pressure, longwave) and a normalised factor for multiplicative ones (wind speed, shortwave, precipitation). Used by disaggregate_met_to_hourly() with method = "diurnal".

Usage

build_diurnal_climatology(hourly, tz = NULL, vars = NULL, n_sub = 24)

Arguments

hourly: data frame with Date (POSIXct) and MET_* columns, e.g. from extract_era5_lake_met().
tz: timezone in which the diurnal cycle is expressed. Defaults to the tz attribute of hourly, else "UTC".
vars: variables to summarise; default all MET_* columns present.
n_sub: steps per day (24 hourly, 8 three-hourly).

Value

object of class diurnal_climatology: a list with shape (a named list of 12 x n_sub matrices), kind ("additive" or "ratio" per variable), n_days per month, tz and n_sub.

Examples

set.seed(1)
h <- data.frame(
  Date = seq(as.POSIXct("2024-01-01", tz = "UTC"),
             by = "hour", length.out = 24 * 60),
  MET_tmpair = 15 + 5 * sin(seq_len(24 * 60) * 2 * pi / 24) + rnorm(24 * 60))
dc <- build_diurnal_climatology(h)
round(dc$shape$MET_tmpair[1, ], 2)
#>  [1]  1.22  2.54  3.45  4.16  4.76  4.83  4.86  4.33  3.45  2.86  1.25  0.07
#> [13] -1.21 -2.42 -3.32 -4.41 -4.77 -5.04 -4.81 -4.31 -3.89 -2.57 -1.23  0.20