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Read CMRSET Actual Evapotranspiration Data from TERN

Source: R/read_aet.R
read_aet.Rd

Wrapper around read_tern() for retrieving the CMRSET actual evapotranspiration data (v2.2) from the TERN Data Portal. This dataset provides monthly estimates of actual ET (mm/month) at 30 m resolution from May 1987 onwards, using the CSIRO MODIS Reflectance-based Scaling Evapotranspiration (CMRSET) algorithm that combines potential evapotranspiration data from the Bureau of Meteorology together with satellite image data provided by MODIS, VIIRS, Landsat and Sentinel-2.

Usage

read_aet(
  date,
  collection = "ETa",
  api_key = NULL,
  max_tries = NULL,
  initial_delay = NULL
)

Arguments

date

A month to download (Date or character, e.g. "2023-06-01" or as.Date("2023-06-01")). The value is snapped to the first of the month internally. Required.

collection

One of "ETa" (actual evapotranspiration in mm/month, default) or "pixel_qa" (quality assurance attributes).

api_key

A character string containing your TERN API key. Defaults to automatic detection from your .Renviron or .Rprofile. See get_key() for setup.

max_tries

Maximum number of download retries before an error is raised. Default=NULL, in which case the maximum retry number is resolved from the option nert.max_tries if that option exists. (Defaults to 3 retries if nert.max_tries has not been set.)

initial_delay

Initial retry delay in seconds (doubles with each attempt). Default=NULL, in which case the initial delay is resolved from the option nert.initial_delay if that option exists. (Defaults to a 1 second initial delay if nert.initial_delay has not been set.)

Value

A terra::SpatRaster object of the requested evapotranspiration collection.

References

McVicar, T., Vleeshouwer, J., Van Niel, T., Guerschman, J. & Peña-Arancibia, J. (2022). Actual Evapotranspiration for Australia using CMRSET algorithm. Version 1.0. Terrestrial Ecosystem Research Network. (Dataset). doi:10.25901/gg27-ck96 .

TERM CMRSET Actual Evapotranspiration Point-of-truth metadata URL: https://geonetwork.tern.org.au/geonetwork/srv/eng/catalog.search#/metadata/9fefa68b-dbed-4c20-88db-a9429fb4ba97

See also

read_tern()

Examples

if (FALSE) { # interactive()
# Actual evapotranspiration (ETa) for June 2023 (mm/month)
r_eta <- read_aet("2023-06-01")
autoplot(r_eta)

# January 2023 ET
r_jan <- read_aet("2023-01-01")

# Quality assurance flags for June 2023
r_qa <- read_aet("2023-06-01", collection = "pixel_qa")

# ET from May 1987 (earliest available)
r_early <- read_aet("1987-05-01")

# Current/recent ET (within last month)
r_recent <- read_aet(Sys.Date())
}