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Download ERA5 Climate Data from the Copernicus CDS API

Source: R/ERA5_download.R
download.ERA5_cds.Rd

Download ERA5 climate data from the Copernicus Climate Data Store (CDS) API as NetCDF files, year by year, according to user-specified parameters. The function saves one NetCDF file per year in the specified output directory.

Usage

download.ERA5_cds(
  outfolder,
  start_date,
  end_date,
  extent,
  variables,
  user,
  key,
  time = NULL,
  dataset = "reanalysis-era5-single-levels",
  product_type = "ensemble_members",
  timeout = 36000
)

Arguments

outfolder

Character. Directory where downloaded NetCDF files will be saved.

start_date

character: the start date of the data to be downloaded. Format is YYYY-MM-DD (will only use the year part of the date)

end_date

character: the end date of the data to be downloaded. Format is YYYY-MM-DD (will only use the year part of the date)

extent

numeric: a vector of numbers contains the bounding box (formatted as xmin, xmax, ymin, ymax) (longitude and latitude in degrees).

variables

character: a vector contains variables to be downloaded (e.g., c("2m_temperature","surface_pressure")).

user

Character. CDS user ID (UID) from your CDS profile. Required for authentication.

key

Character. CDS API key from your CDS profile. Required for authentication.

time

Character vector or NULL. Hours of the day to download (e.g., c("00:00", "12:00")). Default to NULL to download all hours.

dataset

Character. Name of the CDS dataset to use (default: "reanalysis-era5-single-levels").

product_type

Character. Product type to request from CDS (default: "ensemble_members").

timeout

numeric: the maximum time (in seconds) allowed to download the data. The default is 36000 seconds.

Value

A list where each element is a list containing:

file

File path to the downloaded NetCDF file.

host

Host name where the file was downloaded.

startdate

Start date and time of the data in the file.

enddate

End date and time of the data in the file.

mimetype

MIME type of the file ("application/x-netcdf").

formatname

Format name ("ERA5_year.nc").

Details

This function requires a valid CDS API key and the ecmwfr package for accessing the Copernicus Climate Data Store. To get a Copernicus CDS API key, register at https://cds.climate.copernicus.eu/profile. You must provide both user (UID) and key parameters from your CDS profile.

You can check the "CC-BY" license under the 'licences' tab of your profile page.

Author

Dongchen Zhang, Akash

Examples

if (FALSE) { # \dontrun{
# Download ERA5 reanalysis data for 2020
output_dir <- withr::local_tempdir()
era5_files <- download.ERA5_cds(
  outfolder = output_dir,
  start_date = "2020-01-01",
  end_date = "2020-06-30",
  extent = c(-72.2215, -72.1215, 42.4878, 42.5878),
  variables = c("2m_temperature", "surface_pressure"),
  user = "your_cds_user_id",
  key = "your_cds_api_key",
  product_type = "reanalysis"
)

# Download ensemble data for specificed hours only
era5_files <- download.ERA5_cds(
  outfolder = output_dir,
  start_date = "2020-01-01",
  end_date = "2020-12-31",
  extent = c(-83.05, -82.95, 42.95, 43.05),
  variables = "surface_solar_radiation_downwards",
  user = "your_cds_user_id",
  key = "your_cds_api_key",
  time = c("00:00", "12:00")
)
} # }