Downloading data from Compute Canada

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  1. Minimum system requirements
  2. Configuring your computational environment
  3. Downloading source code
  4. Downloading data directories
  5. Creating run directories
  6. Configuring runs
  7. Compiling
  8. Running
  9. Output files
  10. Visualizing and processing output
  11. Coding and debugging
  12. Further reading


On this page, we provide information about how to manually download GEOS-Chem input data (met fields, emissions, etc.) from the Compute Canada storage archive. But we recommend downloading data with the GEOS-Chem dry-run option (which will be available in GEOS-Chem 12.7.0, as this greatly simplifies the data download process.

NOTE: If you have already used the GEOS-Chem dry-run option to download data, you can skip ahead to Creating Run Directories.

Compute Canada directory structure

The GEOS-Chem shared data directories may be downloaded from the Compute Canada server:

http://geoschemdata.computecanada.ca

which has the following directory structure:

Directory Description
ExtData/ Root data directory containing all meteorlogy fields, emissions data, and chemistry input data.
ExtData/CHEM_INPUTS/ Contains non-emissions data for GEOS-Chem chemistry modules
ExtData/HEMCO/ Contains emissions data for the HEMCO emissions component
ExtData/GEOSCHEM_RESTARTS/ Contains sample restart files uses to initialize GEOS-Chem simulations.
0.25° x 0.3125° Data Directories Description
ExtData/GEOS_0.25x0.3125/GEOS_FP/YYYY/MM/ 0.25° x 0.3125° GEOS-FP global met fields
ExtData/GEOS_0.25x0.3125_AS/GEOS_FP/YYYY/MM/ 0.25° x 0.3125° GEOS-FP met fields cropped to the Asia domain
ExtData/GEOS_0.25x0.3125_CH/GEOS_FP/YYYY/MM/ 0.25° x 0.3125° GEOS-FP met fields cropped to the China domain
ExtData/GEOS_0.25x0.3125_EU/GEOS_FP/YYYY/MM/ 0.25° x 0.3125° GEOS-FP met fields cropped to the Europe domain
ExtData/GEOS_0.25x0.3125_NA/GEOS_FP/YYYY/MM/ 0.25° x 0.3125° GEOS-FP met fields cropped to the North America domain
0.5° x 0.625° Data Directories Description
ExtData/GEOS_0.5x0.625/MERRA2/YYYY/MM/ 0.5° x 0.625° MERRA-2 global met fields
ExtData/GEOS_0.5x0.625_AS/MERRA2/YYYY/MM/ 0.5° x 0.625° MERRA-2 met fields cropped to the Asia domain
ExtData/GEOS_0.5x0.625_CH/MERRA2/YYYY/MM/ 0.5° x 0.625° MERRA-2 met fields cropped to the China domain
ExtData/GEOS_0.5x0.625_EY/MERRA2/YYYY/MM/ 0.5° x 0.625° MERRA-2 met fields cropped to the Europe domain
ExtData/GEOS_0.5x0.625_NA/MERRA2/YYYY/MM/ 0.5° x 0.625° MERRA-2 met fields cropped to the North America domain
2° x 2.5° Data Directories Description
ExtData/GEOS_2x2.5/GEOS_FP/YYYY/MM 2° x 2.5° GEOS-FP global met fields
ExtData/GEOS_2x2.5/MERRA2/YYYY/MM 2° x 2.5° MERRA-2 global met fields
4° x 5° Data Directories Description
ExtData/GEOS_4x5/GEOS_FP/YYYY/MM/ 4° x 5° GEOS-FP global met fields
ExtData/GEOS_4x5/MERRA2/YYYY/MM/ 4° x 5° MERRA-2 global met fields

--Bob Yantosca (talk) 19:21, 11 December 2019 (UTC)

GEOS-FP and MERRA-2 constant data files

If you are downloading the GEOS-FP or MERRA-2 met data, then please note that you must also download the "CN" (constant) data files for each horizontal grid that you are using.

For GEOS-FP these are timestamped for 2011/01/01 and are found in these data directories:

  • ExtData/GEOS_0.25x0.3125/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.nc
  • ExtData/GEOS_0.25x0.3125_AS/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.AS.nc
  • ExtData/GEOS_0.25x0.3125_CH/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.CH.nc
  • ExtData/GEOS_0.25x0.3125_EU/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.EU.nc
  • ExtData/GEOS_0.25x0.3125_NA/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.NA.nc
  • ExtData/GEOS_2x2.5/GEOS_FP/2011/01/GEOSFP.20110101.CN.2x25.nc
  • ExtData/GEOS_4x5/GEOS_FP/2011/01/GEOSFP.20110101.CN.4x5.nc

For MERRA-2 these are timestamped for 2015/01/01 and are found in these data directories :

  • ExtData/GEOS_0.5x0.625/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.nc4
  • ExtData/GEOS_0.5x0.625_AS/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.AS.nc4
  • ExtData/GEOS_0.5x0.625_CH/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.CH.nc4
  • ExtData/GEOS_0.5x0.625_EU/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.EU.nc4
  • ExtData/GEOS_0.5x0.625_NA/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.NA.nc4
  • ExtData/GEOS_2x2.5/MERRA2/2015/01/MERRA2.20150101.CN.2x25.nc4
  • ExtData/GEOS_4x5/MERRA2/2015/01/MERRA2.20150101.CN.4x5.nc4

Additional notes:

  • Prior to downloading GEOS-FP data, please be aware of caveats regarding use of GEOS-FP. See the GEOS-FP wiki page for more information.

--Bob Yantosca (talk) 19:20, 11 December 2019 (UTC)

Data download commands

We recommend that you use the free and open-source wget utility to download data from Compute Canada. Most modern Unix systems have wget already installed.

Basic syntax

The basic formula to download data from Compute Canada to your local server is:

wget OPTIONS "http://geoschemdata.computecanada.ca/ExtData/DIRECTORY_NAME"

NOTE: The URL must be enclosed in quotes for file transfer to occur. If you omit the quotes then wget will just return a directory listing in a file named index.html without any files being downloaded.

Commonly used options with wget are:

wget option Description
-np Will not allow ascent to the parent directory
-nH Omits the remote root directory name from the local directory name.
  • i.e. Downloads geoschemdata.computecanada.ca/ExtData/DIRECTORY_NAME to local folder ExtData/DIRECTORY_NAME.
-N Downloads only those files having newer timestamps than any local copies.
-P path Copies data to the specified directory
  • e.g. Specifying -P /home/data will copy geoschemdata.computecanada.ca/ExtData/DIRECTORY_NAME
    to /home/data/ExtData/DIRECTORY_NAME, etc.
-r Specifies recursive directory transfer (i.e. will download all subdirectories).
-R "*.html" Skips downloading files ending in *.html.

Examples

1. Download remote directory geoschemdata.computecanada.ca/ExtData/DIRECTORY_NAME to ./ExtData/DIRECTORY_NAME.

wget -r -np -nH -N -R "*.html" "http://geoschemdata.computecanada.ca/ExtData/DIRECTORY_NAME"


2. Similar to Example 1 above, but will download remote directory geoschemdata.computecanada.ca/ExtData/DIRECTORY_NAME to ./DIRECTORY_NAME. We have used --cut-dirs=1 to trim one level off the downloaded directory.

wget -r -np -nH -N -R "*.html" --cut-dirs=1 "http://geoschemdata.computecanada.ca/ExtData/DIRECTORY_NAME/"


3. Similar to Example 1 above, but wll download the directory geoschemdata.computecanada.ca/ExtData/DIRECTORY_NAME to /pub/gcgrid/data/ExtData/DIRECTORY_NAME:

wget -r -np -nH -N -R "*.html" -P /pub/gcgrid/data "http://geoschemdata.computecanada.ca/ExtData/DIRECTORY_NAME"

Further reading

  1. wget @ GNU.org
  2. Linux wget command help and examples (Computer Hope)
  3. What is the wget command and how to use it? (Hostinger tutorials)



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