Changes between Version 1 and Version 2 of Ticket #145, comment 4


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Timestamp:
10/21/15 18:18:15 (5 years ago)
Author:
stevehankin
Comment:

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  • Ticket #145, comment 4

    v1 v2  
    1818    CMIP6 example:
    1919        model history output files and the file containing the cell_measures field all contain:
    20             external_aggregation_keys = "GFDL_CM2.5_CMIP6_global_lowres_cellMeasures"
     20           
     21{{{
     22 external_aggregation_keys = "GFDL_CM2.5_CMIP6_global_lowres_cellMeasures";
     23}}}
     24
    2125
    2226    time series example
    2327        all model outputs that belong to the same model run contain:
    24            external_aggregation_keys = "GFDL_CM2.5_CMIP6_global_lowres_runstart_21oct2015"
     28         
     29{{{
     30 external_aggregation_keys = "GFDL_CM2.5_CMIP6_global_lowres_runstart_21oct2015";
     31}}}
     32
    2533
    2634    combined aggregation of external cell measures and time series files
    2735        model output history files all contain 2 keys:
    28           external_aggregation_keys = "GFDL_CM2.5_CMIP6_global_lowres_cellMeasures GFDL_CM2.5_CMIP6_global_lowres_runstart_21oct2015"
     36         
     37{{{
     38external_aggregation_keys = "GFDL_CM2.5_CMIP6_global_lowres_cellMeasures GFDL_CM2.5_CMIP6_global_lowres_runstart_21oct2015";
     39}}}
     40
    2941        the cell_measures file contains only 1:
    30            external_aggregation_keys = "GFDL_CM2.5_CMIP6_global_lowres_cellMeasures"
     42
     43{{{
     44 external_aggregation_keys = "GFDL_CM2.5_CMIP6_global_lowres_cellMeasures";
     45}}}
     46
    3147
    3248There is a problem, of course.  In the CMIP6 example the model history output files would fail in a CF conformance tester because the "cell_measures" attributes they contain point to a field that is missing from the file.  However, the creators of these model history files know of this situation as they are writing the files.  They just need a mechanism to indicate it. So we propose a second new CF attribute, "external_references".   In the CMIP6 example above the model history files would need to contain
    3349
    34     external_references = "this_cell_measures_field";
     50   
     51{{{
     52external_references = "this_cell_measures_field";
     53}}}
    3554
    3655(Arguably, the same concern over breaking CF conformance applies to the original proposal: the CF file needs to confess to the variable(s) it is missing.)