Compute climatological baseline

Computes the mean value over a reference period for each variable and period combination. The result is used by cd_anomaly() to calculate departures.

Usage

cd_baseline(x, baseline_years = 1981:2010)

Arguments

x

A tibble from cd_extract() with columns variable, period, year, value.

baseline_years

Integer vector of years to average. Default 1981:2010 (WMO standard).

Value

A tibble with columns variable, period, baseline_mean.

Examples

catalog <- cd_catalog(
  system.file("extdata", "example_catalog.json", package = "cd")
)
aoi <- sf::st_read(
  system.file("extdata", "example_aoi.gpkg", package = "cd"),
  quiet = TRUE
)
ts <- cd_extract(catalog, aoi)

# Early period baseline — pre-warming reference for departure communication
cd_baseline(ts, baseline_years = 1951:1955)
#> # A tibble: 1 × 3
#>   variable period baseline_mean
#>   <chr>    <chr>          <dbl>
#> 1 tmean    annual         -1.44

# Later period baseline — shows how baseline choice affects anomaly magnitude
cd_baseline(ts, baseline_years = 1956:1960)
#> # A tibble: 1 × 3
#>   variable period baseline_mean
#>   <chr>    <chr>          <dbl>
#> 1 tmean    annual         -1.33