Climatology Lab TerraClimate
In amadeus: Accessing and Analyzing Large-Scale Environmental Data

# packages
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = ""
)
library(amadeus)

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
)

cat('[1] "344cddba906371b701f661ccebeef3f427b2d8ec"')

Check the downloaded netCDF files.

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

cat('[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

cat('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 
')