#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 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).