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Web Interface

The Zonda web interface, available at zonda.ethz.ch , serves as the primary platform for users to configure and submit data requests. It provides an intuitive and interactive environment for managing templates, parameters, and domains.

The main features of this frontend are:

  • Configure the desired grid and EXTPAR options directly in the web UI.
  • Preview the domain on either a 2D map or a 3D globe.
  • Generate up to six (nested) domains simultaneously.
  • Generate a JSON file that serves as input for the backend to generate the data.

Select a Template (Optional)

Under Templates, three templates are currently available, derived from operational setups of the ICON community. Selecting a template applies all its settings to the frontend automatically.

The following templates are available:

Global Parameters

In the Global Parameters section, define the grid values n (grid_root) and k (grid_level) for the base grid and customize the output file name.

Domain Specific Parameters

Here, you can add or remove domains. By default, Domain 1 is always present. Add additional domains by clicking the icon to the right. Remove domains by clicking the icon.

Switch between domains by clicking on them. This action updates the view of the sections below (ICON Grid Generation and EXTPAR Parameters).

Preview

Once valid grid numbers are entered, your domain(s) will appear in the preview on the left-hand side. Toggle between 2D (map) and 3D (globe) views as needed.

For domains generated over the pole the usage of the 3D view is recommended, as not all edge cases for visualizations have been covered in the 2D map.

ICON Grid Generation

On the top, an Estimations box shows the estimated resolution in km as well as the number of grid cells based on your domain settings below.

Info

Domain 1 can be set as either a local or global domain by using the provided toggle.

Below, there is a switch to toggle between rectangluar and circular shaped domains.

Tip

Tooltips are available for all user-configurable variables. Hover over the icon to view them.

The following domain settings can be configured:

  • parent_id: Parent grid ID. For example, if Domain 2 is nested within Domain 1, set parent_id to 1 for Domain 2.
  • center_lat: Center point in degrees latitude.
  • center_lon: Center point in degrees longitude.
  • hwidth_lat: Half-width in degrees latitude (rectangular domain only).
  • hwidth_lon: Half-width in degrees longitude (rectangular domain only).
  • radius: Radius of the circular domain in degrees (circular domain only).

Rotated Grid Settings

For rectangular domains, you can enable the rotated grid option using the provided toggle. When activated, you can adjust the following parameters:

  • pole_lat: Latitude of the rotated north pole (in degrees).
  • pole_lon: Longitude of the rotated north pole (in degrees).

If a rotated domain is selected, the resulting output after a successful request will contain two additional files:

  • <domain>_DOM0x_latlon_rotated.nc: a latitude/longitude netCDF grid file in rotated coordinates that matches your defined domain.
  • <domain>_DOM0x_latlon_rotated_reduced.nc: a latitude/longitude netCDF grid file in rotated coordinates that is reduced by 16 cells from each lateral boundary.

These files can then be used to remap unstructured ICON output onto a regular rotated grid, which is particularly useful for the CLM community and regional climate modeling workflows.

EXTPAR Parameters

This section contains all variables required by EXTPAR. For more information, click on a variable name to navigate to the relevant section of the EXTPAR documentation .

Hidden options

There are some options for the ICON Grid Generator and EXTPAR which are supported, but not visible on the Zonda frontend. These are generally advanced options only required by very specific users. They are not shown on the frontend to avoid cluttering the interface for more general users, but can still be used by manually adding them to the JSON config before submitting a Zonda request on GitHub. Below you can find a list of these hidden options (refer to the ICON Tools and EXTPAR documentations for more details).

Part of the "basegrid" section in the JSON config:

  • bdy_indexing_depth

Part of the "icontools" section in the JSON config:

  • number_of_grid_used
  • lsmoothed

Part of the "extpar" section in the JSON config:

  • lurban

Zonda Options

The backend supports different tagged versions of EXTPAR. If necessary, you can select an older version here. By default, the latest version is used.

JSON Request

The web interface automatically generates a JSON code snippet based on the values entered in the sections above.

To proceed:

  1. Use the "Copy and submit request" button.
  2. In the resulting popup, click "Open Request", which redirects you to the data request issue on GitHub.
  3. Follow these steps on GitHub:
    • Replace the line PASTE_YOUR_REQUEST_HERE with the JSON code (automatically copied to your clipboard).
    • Click "Preview" in the issue box to verify the JSON formatting and syntax highlighting.
    • Submit the request by clicking the "Create" button at the bottom right.
    • Later, you can also re-submit requests. For example if the request fails due to an error in the JSON file, simply fix the error by editing the JSON snippet in the description of the issue, then re-submit the request by writing a comment containing the string "rerun request". Note that this only works if the issue is not closed and the request is not already running.

Important

The zonda-request repository is publicly accessible. However, to create a new data request issue (and submit a request), you must have a GitHub user account .

The sidebar on the right offers additional information and tools.

Table of Contents

The table of contents ("On this Page") shows all the available sections. A green marker also indicates the current section in the main frame. It is also possible to click on a section in the sidebar to automatically scroll to it.

Info

If the Expert mode is selected, the section "Zonda Parameters" will appear here.

How to cite Zonda

If you use Zonda-generated data for your publications or reports, please copy the text to acknowledge the developers and their institutions.

RnBk Finder Tool

This tool provides an effective way of finding the best RnBk values for a given grid spacing. To use it, enter the desired resolution (in km) in the input field. If the input is valid, the best RnBk grids (max. 3) are displayed, including their approximate mesh size and the difference to the user's input grid.