North American Regional Reanalysis (NARR)

Download

Start by downloading the netCDF data files with download_data.

• dataset_name = "narr": NARR dataset acronym.
• variable = "air.2m": air temperature at 2m height variable code.
• 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 = "narr",
  variable = "air.2m",
  year = c(2021, 2022),
  directory_to_save = dir,
  acknowledgement = TRUE,
  download = TRUE,
  remove_command = TRUE,
  hash = TRUE
)

[1] "e839448db9634a6534f89f5e8a1d18525dc3b206"

Check the downloaded netCDF files.

list.files(dir, recursive = TRUE, pattern = "air.2m")

[1] "air.2m/air.2m.2021.nc" "air.2m/air.2m.2022.nc"

Process

Import and process the downloaded netCDF files with process_covariates.

• covariate = "narr": NARR dataset acronym.
• variable = "air.2m": air temperature at 2m height variable code.
• date = c("2021-12-28", "2022-01-03"): date range of interest.
• path = paste0(dir, "/air.2m"): directory containing the downloaded files.

air2m_process <- amadeus::process_covariates(
  covariate = "narr",
  variable = "air.2m",
  date = c("2021-12-28", "2022-01-03"),
  path = file.path(dir, "/air.2m")
)

Check the processed SpatRaster object.

air2m_process

class       : SpatRaster 
dimensions  : 277, 349, 7  (nrow, ncol, nlyr)
resolution  : 32462.99, 32463  (x, y)
extent      : -16231.49, 11313351, -16231.5, 8976020  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=lcc +lat_0=50 +lon_0=-107 +lat_1=50 +lat_2=50 +x_0=5632642.22547 +y_0=4612545.65137 +datum=WGS84 +units=m +no_defs 
sources     : air.2m.2021.nc:air  (4 layers) 
              air.2m.2022.nc:air  (3 layers) 
varnames    : air (Daily Air Temperature at 2 m) 
              air (Daily Air Temperature at 2 m) 
names       : air.2~11228, air.2~11229, air.2~11230, air.2~11231, air.2~20101, air.2~20102, ... 
unit        :           K,           K,           K,           K,           K,           K, ... 
time        : 2021-12-28 to 2022-01-03 UTC 

terra::plot(air2m_process[[1]])

Calculate covariates

Calculate covariates for North Carolina county boundaries with calculate_covariates. County boundaries are accessed with the tigris::counties function.

• covariate = "narr": NARR dataset acronym.
• from = air2m_process: processed SpatRaster object.
• locs = tigris::counties("NC", year = 2021): North Carolina county boundaries.
• locs_id = "NAME": county name identifier.
• radius = 0: size of buffer radius around each county.
• geom = "terra": return covariates as a SpatVector object.

library(tigris)
air2m_covar <- amadeus::calculate_covariates(
  covariate = "narr",
  from = air2m_process,
  locs = tigris::counties("NC", year = 2021),
  locs_id = "NAME",
  radius = 0,
  geom = "terra"
)

Check the calculated covariates SpatVector object.

air2m_covar

class       : SpatVector 
geometry    : polygons 
dimensions  : 700, 3  (geometries, attributes)
extent      : 7731783, 8506154, 3248490, 3694532  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=lcc +lat_0=50 +lon_0=-107 +lat_1=50 +lat_2=50 +x_0=5632642.22547 +y_0=4612545.65137 +datum=WGS84 +units=m +no_defs 
names       :     NAME       time air.2m_0
type        :    <chr>   <POSIXt>    <num>
values      :  Chatham 2021-12-28    289.3
              Alamance 2021-12-28    288.8
              Davidson 2021-12-28    289.1