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Data sources and accounts

Most data the Case Builder uses are open downloads. Three sources need an account of your own. Your logins stay on your computer: the Builder reads them from your own files or environment variables, and never writes them into a case.

SourceNeeded forAccount
Copernicus Climate Data Store (CDS)ERA5 weather, ERA5-Land starting soil water, ERA5 rain, and the GloFAS and GTSM boundariesfree, every case made in the app
NASA EarthdataIMERG rain, and leaf area when the ORNL MODIS service is unavailablefree
MSWEP (GloH2O)MSWEP rainapproval from GloH2O, and rclone for its Google Drive folder

AORC rain (United States) and the static maps (terrain, basins, land cover, soils, groundwater) need no account. Leaf area comes from the ORNL MODIS web service, with no account. When that service is unavailable, the Builder takes it from NASA LP DAAC, which uses your Earthdata login.

The page checks the accounts before it downloads anything. When one is missing, a yellow box says "This case cannot be prepared yet:" and names it, and Prepare complete case stays greyed out.

Copernicus Climate Data Store​

  1. Create an account at the Copernicus Climate Data Store.

  2. Log in and accept the terms of use of the ERA5 and ERA5-Land datasets.

  3. Copy your personal access token from your CDS profile page.

  4. Create a text file named .cdsapirc in your home folder with these two lines:

    url: https://cds.climate.copernicus.eu/api
    key: YOUR_CDS_PERSONAL_ACCESS_TOKEN

    On a Mac the file is ~/.cdsapirc, on Windows %USERPROFILE%\.cdsapirc. On a Mac, protect it with chmod 600 ~/.cdsapirc.

The token can also come from the environment variable CDSAPI_KEY. CDS puts each request in a queue, so the first download of a case can wait some minutes before it starts.

NASA Earthdata​

  1. Create a NASA Earthdata Login account and accept the terms for GPM IMERG data.

  2. Generate a token in your Earthdata profile.

  3. Save the token, alone on one line, in this file:

    • Mac: ~/.config/hydropol2d-case-builder/earthdata_token
    • Windows: %USERPROFILE%\.config\hydropol2d-case-builder\earthdata_token

    On a Mac, protect the folder and the file:

    mkdir -p ~/.config/hydropol2d-case-builder
    chmod 700 ~/.config/hydropol2d-case-builder
    chmod 600 ~/.config/hydropol2d-case-builder/earthdata_token

The Builder also accepts the token in the environment variable EARTHDATA_TOKEN, a ~/.netrc file with your Earthdata login, or the variables EARTHDATA_USERNAME and EARTHDATA_PASSWORD.

MSWEP​

MSWEP needs prior approval from GloH2O.

  1. Ask for access on the MSWEP page. The approval email gives you a shared Google Drive folder.

  2. Install rclone (on a Mac with Homebrew: brew install rclone).

  3. Run rclone config and create a remote named GoogleDrive of type drive. Complete the authorization in your browser, and do not set the shared folder up as a Team Drive.

  4. Check that the shared folder is visible:

    rclone lsd --drive-shared-with-me GoogleDrive:

When you choose MSWEP (hourly) or MSWEP (3 hourly), the page searches your rclone remotes for the authorized MSWEP folder. When it finds one, it says "Authorized MSWEP V3.16 folder found. Automatic MSWEP download is ready." and fills MSWEP rclone folder and Shared-folder ID (optional). Both stay visible, and you can change them. The Builder downloads only the time steps of the case, cuts them to the domain, and records the source in quality_report/mswep_download.json. When a request crosses the end of the Past record, the later time steps come from the NRT (near real time) folder by themselves.

The page warns that MSWEP V3.16 has a documented artificial trend in precipitation around 2015. For trend studies over 1979 to 2021, use V2.80. Recent NRT files are preliminary and are revised after their first release. MSWEP V3 is cited as Wang et al. (2026), MSWEP V3.

If you already have the rainfall as files, use Existing rainfall directory (optional) instead (Case settings).

Data licenses​

The input datasets keep their own licenses and access terms, and you follow them when you use their data. Each case records every source and its version in quality_report/public_static_sources.json and in its manifest.json.