Data Resources: How to Create and FTP a netCDF File Subset

  1. First, go to the general search page to find the data you want to retrieve.
  2. Highlight (click on) the dataset(s) and/or variable(s) that are of interest. For example choose:
    Data Set: NCEP
    Variable: Sea Level Pressure
  3. Push the Submit button. This will return to you a list of SLP files from the NCEP data set.
  4. Choose the map icon to create a plot or a subset for the data of interest.
  5. Enter the geographic region you are interested in.  The longitudes should be entered in increasing easterly order (I.E., the easternmost point last of the pair of values).  The latitudes should likewise be entered in south to north order.
  6. Select the start and end time. If you want the whole time span you should select the first time on the left menu and the last time on the right menu.
  7. If you want to create the subset without making a plot first select the "Create a subset without a making a plot" radio button and push the Create Plot or Subset of Data button.
  8. At this point you should have a web page containing a link to the file subset. If you follow this link, most browsers are set up to prompt you to save the file on your local disk. Alternatively, position your cursor over the link and hold down your right mouse button. This action should result in a browser menu with a "Save Link As..." option. Select this option to save the file on your local disk.

NOTE: If you make a plot it will be the AVERAGE of the time steps (and other ranges like the levels in the z direction), but the file contains the individual time steps.