Get PatchedPoint Weather Data in the APSIM Format From SILO

Fetch APSIM .met file formatted weather data from the SILO API derived from the BOM station observations (PatchedPoint) data.

Usage

get_patched_point_apsim(
  station_code,
  start_date,
  end_date = Sys.Date(),
  api_key = get_key(service = "SILO")
)

Arguments

station_code: A character string or factor from get_stations_metadata() of the BOM station code for the station of interest.
start_date: A character string or Date object representing the beginning of the range to query in the format “yyyy-mm-dd” (ISO8601). Data returned is inclusive of this date.
end_date: A character string or Date object representing the end of the range query in the format “yyyy-mm-dd” (ISO8601). Data returned is inclusive of this date. Defaults to the current system date.
api_key: A character string containing your API key, an e-mail address, for the request. Defaults to automatically detecting your key from your local .Renviron, .Rprofile or similar. Alternatively, you may directly provide your key as a string here. If nothing is provided, you will be prompted on how to set up your R session so that it is auto-detected.

Value

An apsimx object of class ‘met’ with attributes.

Details

The SILO documentation provides the following information for the PatchedPoint data.

These data are a continuous daily time series of data at either recording stations or grid points across Australia:

Data at station locations consists of observational records which have been supplemented by interpolated estimates when observed data are missing. Datasets are available at approximately 8,000 Bureau of Meteorology recording stations around Australia.
Data at grid points consists entirely of interpolated estimates. The data are taken from the SILO gridded datasets and are available at any pixel on a 0.05° × 0.05° grid over the land area of Australia (including some islands).

Included Values

rain (mm): Rainfall
maxt (degrees C): Maximum temperature
mint (degrees C): Minimum temperature
vp (hPa): Vapour pressure
evap_pan (mm): Class A pan evaporation
radiation (Mj/m¹): Solar exposure, consisting of both direct and diffuse components

Value information

Solar radiation: total incoming downward shortwave radiation on a horizontal surface, derived from estimates of cloud oktas and sunshine duration².

Evaporation and evapotranspiration: an overview of the variables provided by SILO is available here, https://data.longpaddock.qld.gov.au/static/publications/Evapotranspiration_overview.pdf.

Data codes

Where the source code is a 6 digit string comprising the source code for the 6 variables. The single digit code for each variable is:

0: an actual observation;
1: an actual observation from a composite station;
2: a value interpolated from daily observations;
3: a value interpolated from daily observations using the anomaly interpolation method for CLIMARC data;
6: a synthetic pan value; or
7: an interpolated long term average.

Saving objects

To save “met” objects the apsimx::write_apsim_met() is reexported. Note that when saving, comments from SILO will be included, but these will not be printed as a part of the resulting met object in your R session.

References

Rayner, D. (2005). Australian synthetic daily Class A pan evaporation. Technical Report December 2005, Queensland Department of Natural Resources and Mines, Indooroopilly, Qld., Australia, 40 pp.
Morton, F. I. (1983). Operational estimates of areal evapotranspiration and their significance to the science and practice of hydrology, Journal of Hydrology, Volume 66, 1-76.

Author

Rodrigo Pires, rodrigo.pires@dpird.wa.gov.au, and Adam Sparks, adamhsparks@gmail.com

Examples

if (FALSE) { # \dontrun{
# requires an API key as your email address
# Source observation data for Wongan Hills station, WA (008137)
wd <- get_patched_point_apsim(
  station_code = "008137",
  start_date = "20220101",
  end_date = "20221231",
  api_key = "your_api_key"
)
} # }