# Climatology Lab TerraClimate

#### Mitchell Manware

#### 2025-08-24

This vignette demonstrates how to download, process, and calculate covariates from the Climatology Lab’s TerraClimate dataset using `amadeus` functions. Details are provided for each function’s parameters and outputs. The examples utilize monthly wind speed data. See https://www.climatologylab.org/wget-terraclimate.html for full variable names and acronyms. The messages returned by `amadeus` functions have been omitted for brevity.

### Download

Start by downloading the netCDF data files with `download_data`.

- `dataset_name = "terraclimate"`: TerraClimate dataset name.
- `variable = "Wind Speed"`: wind speed variable name.
- `year = c(2021, 2022)`: years of interest.
- `directory_to_save = dir`: directory to save the downloaded files.
- `acknowledgement = TRUE`: acknowledge that the raw data files are large and may consume lots of local storage.
- `download = TRUE`: download the data files.
- `remove_command = TRUE`: remove the temporary command file used to download the data.
- `hash = TRUE`: generate unique SHA-1 hash for the downloaded files.

    dir <- tempdir()
    amadeus::download_data(
      dataset_name = "terraclimate",
      variable = "Wind Speed",
      year = c(2021, 2022),
      directory_to_save = dir,
      acknowledgement = TRUE,
      download = TRUE,
      remove_command = TRUE,
      hash = TRUE
    )

    [1] "344cddba906371b701f661ccebeef3f427b2d8ec"

Check the downloaded netCDF files.

    list.files(dir, recursive = TRUE, pattern = "ws")

    [1] "ws/ws_2021.nc" "ws/ws_2022.nc"

### Process

Import and process the downloaded netCDF files with `process_covariates`.

Parameters:

- `covariate = "terraclimate"`: TerraClimate dataset name.
- `variable = "Wind Speed"`: wind speed variable name.
- `date = c("2021-12-28", "2022-01-03")`: date range of interest.
- `path = paste0(dir, "/ws")`: directory containing the downloaded files.

    ws_process <- amadeus::process_covariates(
      covariate = "terraclimate",
      variable = "Wind Speed",
      date = c("2021-12-28", "2022-01-03"),
      path = file.path(dir, "/ws")
    )

Check the processed `SpatRaster` object. Note Climatology Lab TerraClimate is a monthly dataset, so the `SpatRaster` contains two layers for December 2021 and January 2022.

    ws_process

    class       : SpatRaster
    dimensions  : 4320, 8640, 2  (nrow, ncol, nlyr)
    resolution  : 0.04166667, 0.04166667  (x, y)
    extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
    coord. ref. : +proj=longlat +ellps=WGS84 +no_defs
    sources     : ws_2021.nc
                  ws_2022.nc
    varnames    : ws (wind speed)
                  ws (wind speed)
    names       : ws_202112, ws_202201
    unit        :       m/s,       m/s
    time (days) : 2021-12-01 to 2022-01-01

    terra::plot(ws_process[[1]])

### Calculate covariates

Covariate calculation with Climatology Lab TerraClimate data is undergoing updates.