Common validation errors and how to solve them!

#1: Requesting parameters that do not exist for the specified stream/levtype

Typical error message

UserError: Ambiguous value 'XXX' could be 'XXX'
Examples

Example 1

  • Scenario: The user requests parameter 'swh' for stream 'oper'.
  • Problem: Parameter 'swh' does not exist for stream 'oper'. 'swh' is a wave product, belonging to stream 'wave'.

To check which parameters are available for which stream, please refer to the ECMWF Real-time Catalogue.

Example 2

  • Scenario: The user requests pressure level data after a preceding surface level data request
  • Problem: Parameter 'u' is a pressure level parameter. The requested 'levtype' is 'sfc' (surface).


  • Tip: Use the inheritance (info) tooltip to confirm which keys/values you are inheriting from the preceding request. 
Solutions

Solution 1.1

  • The user does not want parameter 'swh' and modifies the request, specifying the correct intended parameter (as suggested by the error message).


Alternative solution 1.2

  • The user needs parameter 'swh' and writes a new request for wave products, using snippets <> for guidance. 


Tip #1 click on the snippets <> icon to browse a list of template requirements for each data set (note that snippets are named according to the ECMWF Real-time Catalogue. If you have trouble finding a snippet, please try searching by the names in the catalogue.

Solution 2

  • The user modifies the second 'disseminate' request, changing 'levtype' to 'pl' (pressure level) and adding the 'levelist' keyword. 

Tip #1 press ctrl + space to see the list of available options for each keyword


Tip #2 click on the snippets <> icon to browse a list of template requirements for each data set (note that snippets are named according to the ECMWF Real-time Catalogue. If you have trouble finding a snippet, please try searching by the names in the catalogue.

#2: Requesting steps>0 for type=an 

Typical error message

param=XX not valid for step=3,time=XXXX
Examples

Example 1

  • Scenario: The user requests steps 0/to/144/by/3 for 'type=an'
  • Problem: Only time step 0 is available for 'type=an'

Solutions

Solution 1.1

  • The user modifies the step to 0.

Solution 1.2

  • The user modifies the type to 'fc' (forecast) and requests all steps as per the original failing request

#3: Area coordinates are in the wrong order 

Typical error message

invalid area, expecting -90 <= S <= N <= 90
Examples

Example 1

  • Scenario: The user requests area '60/-180/90/180'
  • Problem: The coordinates are read as N/W/S/E, the northern most latitude must be specified first.

Solutions

Solution 1

  • The user modifies the area, specifying the northern (90) and southern (60) points in the correct order (N/W/S/E).