Bioclimatic variables over an arbitrary window of months

Computes the 19 standard bioclimatic variables over a user-defined subset of months. This is useful when a species' relevant season does not coincide with fixed quarters (e.g. eBird Status & Trends breeding windows).

Usage

bioclim_window(
  tas,
  tasmax,
  tasmin,
  pr,
  months = NULL,
  start = NULL,
  end = NULL,
  window = 3L,
  na.rm = FALSE,
  ...
)

Arguments

tas

Numeric vector (length 12), matrix (pixels x 12), SpatRaster with 12 layers, or BioclimData.

tasmax

Same form as tas: monthly maximum temperature.

tasmin

Same form as tas: monthly minimum temperature.

pr

Same form as tas: monthly precipitation.

months

Integer vector of 1-based months in the window, e.g. c(6, 7) for Jun-Jul or c(12, 1, 2) for DJF. If start and end are supplied, months is derived automatically.

start, end

Optional character strings in "MM-DD" format. When both are supplied, the months that overlap the day range are selected. Wrap-around across the year end is supported.

window

Integer: length of the internal rolling sub-window used to compute bio08..bio19. Defaults to 3 (quarterly). Must be <= length(months) for the rolling variables to be non-NA.

na.rm

Logical. If FALSE (default), a single NA among the selected months makes all outputs NA for that pixel. If TRUE, missing months are skipped.

...

Not currently used.

Value

• Vector input: a named numeric vector of length 19 (bio01..bio19).

• Matrix / BioclimData input: a numeric matrix (pixels x 19).

• SpatRaster input: a 19-layer SpatRaster.

Details

The base variables (bio01..bio07, bio12..bio15) are computed directly over the selected months. The rolling variables (bio08..bio11, bio16..bio19) are computed over the best contiguous window-month period that is fully contained in months. If length(months) < window or no such contiguous period exists, those columns are NA.

See also

bioclim_rolling() for rolling optimal windows over the full year with a free window length.