Data Access

We have published the first set of NA-CORDEX data to the CDG data portal. This dataset includes:

  • precipitation (pr)
  • temperature (tas)
  • daily minimum temperature (tasmin)
  • daily maximum temperature (tasmax)

for all of the simulations shown in the Simulation Matrix except those marked as "in progress".

You can download data from the NA-CORDEX search page on the Climate Data Gateway.

Downloading Data

The NA-CORDEX search page on the NCAR Climate Data Gateway data portal lists options for different data facets of the collection. Use the checkboxes to select the features you want, then click the "Search" button.

Matching results will be listed below on the same page. You can download individual files by clicking on their names. To download multiple files in a batch, you can select them using checkboxes, then click "Download Wget Script"; the resulting script can be run natively on Linux and Mac systems and in a Linux emulator or virtual machine on Windows systems.

For example, if you were interested in monthly-average temperature and precipitation from ERA-Interim driven runs at 25-km resolution on the native grid, you'd select "pr" and "tas" under Variables, "ERA-Int" under Driver, "mon" under Frequency, and "NAM-22" under Grid. Because nothing was selected under Model, the search will return results for all models with data fitting the other criteria. Within a category, the search returns results matching any of the selections; between categories, the results must match a selection in each category.

Subsetting Data

The CDG data portal will now allow you to subset the data to a region of interest. To the right of each file in a search result is a "Subset" link that will take you to the NetCDF Subset Service built into the data portal engine.

To subset data, first, click the checkbox to select the variable. Although NA-CORDEX files only contain one data variable, the engine doesn't yet know to automatically select it. Next, unselect "disable horizontal subsetting" below the map. You can now enter values for a lat-lon bounding box. Click the "Submit" button at the bottom of the page (you may need to scroll down) to download the subset data.

Notes: The map showing the spatial coverage of the data is interactive. You cannot click and drag to define the bounding box, but you can zoom in and mouse over to find out the lat and lon coordinates of various features on the map. For NA-CORDEX data, longitude values will generally be negative. The bounding box must fit entirely within the spatial domain of the data. For data on the native grid, trying to use the default extent will generate an error, because a lat-lon rectangle containing all the data also contains regions outside the spatial domain. If you encounter an error, don't forget to redo the first two steps when you go back to the subset page. You can also subset the data in time.

Data Availability

Some frequencies and grids are not yet available, but daily data on the native grid should be available for all published simulations. Sub-daily precipitation is available for the CanRCM4 simulations and for RegCM4 driven by MPI. The data portal usually goes offline briefly once a week for software updates.